WorldWideScience

Sample records for rapid energy transfer

  1. 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...

  2. Rapid and facile ratiometric detection of an anthrax biomarker by regulating energy transfer process in bio-metal-organic framework.

    Science.gov (United States)

    Zhang, Yihe; Li, Bin; Ma, Heping; Zhang, Liming; Zheng, Youxuan

    2016-11-15

    A ratiometric fluorescent sensor based on luminescent bio-metal-organic framework was prepared by exchanging both Tb(3+) and Eu(3+) cations into anionic bio-MOF-1. Due to a highly efficient energy transfer from Tb(3+) to Eu(3+) (>89%), emission color of Tb/Eu@bio-MOF-1 was orange-red even though Tb(3+) was the dominant content in this Tb/Eu co-doping material. More interestingly, this energy transfer process could be modulated by dipicolinic acid (DPA), an unique biomarker for bacillus spores. With DPA addition, corresponding DPA-to-Tb(3+) energy transfer was gradually enhanced while the energy transfer from Tb(3+) to Eu(3+) was significantly weakened. By regulating the energy transfer process in Tb/Eu@bio-MOF-1, visual colorimetric sensing of DPA in porous MOF was realized for the first time. Detection limit of Tb/Eu@bio-MOF-1 for DPA was 34nM, which was much lower than an infectious dosage of Bacillus anthracis spores (60μM) for human being. Besides, Tb/Eu@bio-MOF-1 showed a remarkable selectivity over other aromatic ligands and amino acids. More importantly, this porous ratiometric sensor worked equally well in human serum. These particularly attractive features of Tb/Eu@bio-MOF-1 made the direct, rapid and naked-eye detection of DPA for practical application possible. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. 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.

  4. Rapid crystallization of a-Si:H films with various silicon-to-hydrogen bonding configurations using rapid energy transfer annealing

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Y.-L. [Department of Electrical Engineering, National Chung Hsing University, Taichung 402, Taiwan (China)]. E-mail: yljiang@nchu.edu.tw; Chang, Y.-C. [Department of Electrical Engineering, National Chung Hsing University, Taichung 402, Taiwan (China)

    2006-04-03

    Hydrogenated amorphous silicon (a-Si:H) films were prepared by changing substrate temperature of plasma-enhanced chemical vapor deposition to induce different contents of monohydride and polyhydride bonds, which were then crystallized into polysilicon (poly-Si) films by rapid energy transfer annealing. Fourier transform infrared and transmission spectra show that the formation of numerous polyhydride bonds increases the hydrogen content and reduces the refractive index of a-Si:H films. The rise in the concentration of polyhydride bonds in as-deposited a-Si:H films can result in the increase of ultraviolet reflectance, small peak shift, and change in full width at half maximum of Raman scattering and X-ray diffraction peaks of the obtained poly-Si films after annealing. These results demonstrate that high-concentration polyhydride bonds can promote the rapid crystallization of a-Si:H and obtain high-crystallinity poly-Si films. Transmission electron microscopy identifies that the poly-Si films have the typical dendrite-like grain structure.

  5. Rapid peptide based diagnosis: peptide-based Fluorescence Resonance Energy Transfer (FRET) protease substrates for the detection and diagnosis of bacillus spp

    NARCIS (Netherlands)

    Bikker, F.J.; Kaman, W.E.

    2014-01-01

    We describe the development of a highly specific protease-based Fluorescence Resonance Energy Transfer (FRET) assay for easy and rapid detection both in vitro and in vivo of Bacillus spp, including Bacillus anthracis. Synthetic substrates for B. anthracis proteases were designed and exposed to

  6. Intramolecular Energy Transfer, Charge Transfer & Hydrogen Bond

    Indian Academy of Sciences (India)

    Ultrafast Dynamics of Chemical Reactions in Condensed Phase: Intramolecular Energy Transfer, Charge Transfer & Hydrogen Bond · PowerPoint Presentation · Slide 3 · Slide 4 · Slide 5 · Slide 6 · Slide 7 · Slide 8 · Slide 9 · Slide 10 · Slide 11 · Slide 12 · Slide 13 · Slide 14 · Slide 15 · Slide 16 · Slide 17 · Slide 18 · Slide 19.

  7. Rapid Energy Modeling Workflow Demonstration

    Science.gov (United States)

    2013-10-31

    BIM Building Information Modeling BPA Building Performance Analysis BTU British Thermal Unit CBECS Commercial Building ...geometry, orientation, weather, and materials, generates 3D Building Information Models ( BIM ) guided by satellite views of building footprints and...Rapid Energy Modeling (REM) workflows that employed building information modeling ( BIM ) approaches and conceptual energy analysis.

  8. Energy transfer with semiconductor nanocrystals

    NARCIS (Netherlands)

    Rogach, A.L.; Klar, T.A.; Lupton, J.M.; Meijerink, A.; Feldmann, J.

    2009-01-01

    Fo¨ rster (or fluorescence) resonant energy transfer (FRET) is a powerful spectroscopic technique to study interactions, conformational and distance changes, in hybrid nanosystems. Semiconductor nanocrystals, also known as colloidal quantum dots, are highly efficient fluorophores with a strong

  9. Energy transfer processes in solar energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Fayer, M.D.

    1986-11-01

    By combining picosecond optical experiments and detailed statistical mechanics theory we continue to increase our understanding of the complex interplay of structure and dynamics in important energy transfer situations. A number of different types of problems will be focused on experimentally and theoretically. They are excitation transport among chromophores attached to finite size polymer coils; excitation transport among chromophores in monolayers, bilayers, and finite and infinite stacks of layers; excitation transport in large vesicle systems; and photoinduced electron transfer in glasses and liquids, focusing particularly on the back transfer of the electron from the photogenerated radical anion to the radical cation. 33 refs., 13 figs.

  10. RRTM: A rapid radiative transfer model

    Energy Technology Data Exchange (ETDEWEB)

    Mlawer, E.J.; Taubman, S.J.; Clough, S.A. [Atmospheric and Environmental Research, Inc., Cambridge, MA (United States)

    1996-04-01

    A rapid radiative transfer model (RRTM) for the calculation of longwave clear-sky fluxes and cooling rates has been developed. The model, which uses the correlated-k method, is both accurate and computationally fast. The foundation for RRTM is the line-by-line radiative transfer model (LBLRTM) from which the relevant k-distributions are obtained. LBLRTM, which has been extensively validated against spectral observations e.g., the high-resolution sounder and the Atmospheric Emitted Radiance Interferometer, is used to validate the flux and cooling rate results from RRTM. Validations of RRTM`s results have been performed for the tropical, midlatitude summer, and midlatitude winter atmospheres, as well as for the four Intercomparison of Radiation Codes in Climate Models (ICRCCM) cases from the Spectral Radiance Experiment (SPECTRE). Details of some of these validations are presented below. RRTM has the identical atmospheric input module as LBLRTM, facilitating intercomparisons with LBLRTM and application of the model at the Atmospheric Radiation Measurement Cloud and Radiation Testbed sites.

  11. Stray energy transfer during endoscopy.

    Science.gov (United States)

    Jones, Edward L; Madani, Amin; Overbey, Douglas M; Kiourti, Asimina; Bojja-Venkatakrishnan, Satheesh; Mikami, Dean J; Hazey, Jeffrey W; Arcomano, Todd R; Robinson, Thomas N

    2017-10-01

    Endoscopy is the standard tool for the evaluation and treatment of gastrointestinal disorders. While the risk of complication is low, the use of energy devices can increase complications by 100-fold. The mechanism of increased injury and presence of stray energy is unknown. The purpose of the study was to determine if stray energy transfer occurs during endoscopy and if so, to define strategies to minimize the risk of energy complications. A gastroscope was introduced into the stomach of an anesthetized pig. A monopolar generator delivered energy for 5 s to a snare without contacting tissue or the endoscope itself. The endoscope tip orientation, energy device type, power level, energy mode, and generator type were varied to mimic in vivo use. The primary outcome (stray current) was quantified as the change in tissue temperature (°C) from baseline at the tissue closest to the tip of the endoscope. Data were reported as mean ± standard deviation. Using the 60 W coag mode while changing the orientation of the endoscope tip, tissue temperature increased by 12.1 ± 3.5 °C nearest the camera lens (p energy transfer (p = 0.04 and p = 0.002, respectively) as did utilizing the low-voltage cut mode (6.6 ± 0.5 °C, p energy transfer compared to a standard generator (1.5 ± 3.5 °C vs. 9.5 ± 0.8 °C, p energy is transferred within the endoscope during the activation of common energy devices. This could result in post-polypectomy syndrome, bleeding, or perforation outside of the endoscopist's view. Decreasing the power, utilizing low-voltage modes and/or an impedance-monitoring generator can decrease the risk of complication.

  12. Energy transfer in macromolecular arrays

    Science.gov (United States)

    Andrews, David L.; Jenkins, Robert D.

    2003-11-01

    Macromolecular systems comprised of many light-sensitive centres (the photosynthetic unit, dendrimers, and other highly symmetric multichromophore arrays) are important structures offering challenges to theoreticians and synthetic chemists alike. Here we outline novel photophysical interactions predicted and observed in such arrays. Using the tools of molecular quantum electrodynamics (QED) we present quantum amplitudes for a variety of higher-order resonance energy transfer (RET) schemes associated with well-known nonlinear optical effects such as two- and three-photon absorption. The initial analysis is extended to account for situations where the participant donor species are identical and exist in a highly symmetric environment, leading to the possible formation of excitons. It emerges from the QED theory that such excitons are closely associated with the higher-order RET processes. General results are interpreted by analyzing particular molecular architectures which offer interesting features such as rate enhancement or limitation and exciton pathway quenching. Applications in the areas of photosynthesis, molecular logic gates and low-intensity fluorescence energy transfer are predicted.

  13. Coherence in Energy Transfer and Photosynthesis

    Science.gov (United States)

    Chenu, Aurélia; Scholes, Gregory D.

    2015-04-01

    Ultrafast energy transfer is used to transmit electronic excitation among the many molecules in photosynthetic antenna complexes. Recent experiments and theories have highlighted the role of coherent transfer in femtosecond studies of these proteins, suggesting the need for accurate dynamical models to capture the subtle characteristics of energy transfer mechanisms. Here we discuss how to think about coherence in light harvesting and electronic energy transfer. We review the various fundamental concepts of coherence, spanning from classical phenomena to the quantum superposition, and define coherence in electronic energy transfer. We describe the current status of experimental studies on light-harvesting complexes. Insights into the microscopic process are presented to highlight how and why this is a challenging problem to elucidate. We present an overview of the applicable dynamical theories to model energy transfer in the intermediate coupling regime.

  14. Rapid Energy Modeling Workflow Demonstration Project

    Science.gov (United States)

    2014-01-01

    BIM Building Information Model BLCC building life cycle costs BPA Building Performance Analysis CAD computer assisted...utilizes information on operations, geometry, orientation, weather, and materials, generating Three-Dimensional (3D) Building Information Models ( BIM ...executed a demonstration of Rapid Energy Modeling (REM) workflows that employed building information modeling ( BIM ) approaches and

  15. 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.

  16. Optical Energy Transfer and Conversion System

    Science.gov (United States)

    Stone, William C. (Inventor); Hogan, Bartholomew P. (Inventor)

    2015-01-01

    An optical power transfer system comprising a fiber spooler, a fiber optic rotary joint mechanically connected to the fiber spooler, and an electrical power extraction subsystem connected to the fiber optic rotary joint with an optical waveguide. Optical energy is generated at and transferred from a base station through fiber wrapped around the spooler, through the rotary joint, and ultimately to the power extraction system at a remote mobility platform for conversion to another form of energy.

  17. Targeting Low-Energy Ballistic Lunar Transfers

    Science.gov (United States)

    Parker, Jeffrey S.

    2010-01-01

    Numerous low-energy ballistic transfers exist between the Earth and Moon that require less fuel than conventional transfers, but require three or more months of transfer time. An entirely ballistic lunar transfer departs the Earth from a particular declination at some time in order to arrive at the Moon at a given time along a desirable approach. Maneuvers may be added to the trajectory in order to adjust the Earth departure to meet mission requirements. In this paper, we characterize the (Delta)V cost required to adjust a low-energy ballistic lunar transfer such that a spacecraft may depart the Earth at a desirable declination, e.g., 28.5(white bullet), on a designated date. This study identifies the optimal locations to place one or two maneuvers along a transfer to minimize the (Delta)V cost of the transfer. One practical application of this study is to characterize the launch period for a mission that aims to launch from a particular launch site, such as Cape Canaveral, Florida, and arrive at a particular orbit at the Moon on a given date using a three-month low-energy transfer.

  18. Wireless energy transfer between anisotropic metamaterials shells

    Energy Technology Data Exchange (ETDEWEB)

    Díaz-Rubio, Ana; Carbonell, Jorge; Sánchez-Dehesa, José, E-mail: jsdehesa@upv.es

    2014-06-15

    The behavior of strongly coupled Radial Photonic Crystals shells is investigated as a potential alternative to transfer electromagnetic energy wirelessly. These sub-wavelength resonant microstructures, which are based on anisotropic metamaterials, can produce efficient coupling phenomena due to their high quality factor. A configuration of selected constitutive parameters (permittivity and permeability) is analyzed in terms of its resonant characteristics. The coupling to loss ratio between two coupled resonators is calculated as a function of distance, the maximum (in excess of 300) is obtained when the shells are separated by three times their radius. Under practical conditions an 83% of maximum power transfer has been also estimated. -- Highlights: •Anisotropic metamaterial shells exhibit high quality factors and sub-wavelength size. •Exchange of electromagnetic energy between shells with high efficiency is analyzed. •Strong coupling is supported with high wireless transfer efficiency. •End-to-end energy transfer efficiencies higher than 83% can be predicted.

  19. Energy and centrality dependence of rapidity densities at RHIC energies.

    Science.gov (United States)

    Wang, X N; Gyulassy, M

    2001-04-16

    The energy and centrality dependence of the charged multiplicity per participant nucleon is shown to be able to differentiate between final state saturation and fixed scale perturbative QCD models of initial entropy production in high-energy heavy-ion collisions. The energy dependence is shown to test the nuclear enhancement of the minijet component of the initial conditions, while the centrality dependence provides a key test of whether gluon saturation is reached at RHIC energies. The HIJING model predicts that the rapidity density per participant increases with centrality, while the saturation model prediction is essentially independent of centrality.

  20. Excitation energy transfer in the photosystem I

    Energy Technology Data Exchange (ETDEWEB)

    Webber, Andrew N

    2012-09-25

    Photosystem I is a multimeric pigment protein complex in plants, green alage and cyanobacteria that functions in series with Photosystem II to use light energy to oxidize water and reduce carbon dioxide. The Photosystem I core complex contains 96 chlorophyll a molecules and 22 carotenoids that are involved in light harvesting and electron transfer. In eucaryotes, PSI also has a peripheral light harvesting complex I (LHCI). The role of specific chlorophylls in excitation and electron transfer are still unresolved. In particular, the role of so-called bridging chlorophylls, located between the bulk antenna and the core electron transfer chain, in the transfer of excitation energy to the reaction center are unknown. During the past funding period, site directed mutagenesis has been used to create mutants that effect the physical properties of these key chlorophylls, and to explore how this alters the function of the photosystem. Studying these mutants using ultrafast absorption spectroscopy has led to a better understanding of the process by which excitation energy is transferred from the antenna chlorophylls to the electron transfer chain chlorophylls, and what the role of connecting chlorophylls and A_0 chlorophylls is in this process. We have also used these mutants to investigate whch of the central group of six chlorophylls are involved in the primary steps of charge separation and electron transfer.

  1. Ultrafast energy transfer within the photosystem II core complex.

    Science.gov (United States)

    Pan, Jie; Gelzinis, Andrius; Chorošajev, Vladimir; Vengris, Mikas; Senlik, S Seckin; Shen, Jian-Ren; Valkunas, Leonas; Abramavicius, Darius; Ogilvie, Jennifer P

    2017-06-14

    We report 2D electronic spectroscopy on the photosystem II core complex (PSII CC) at 77 K under different polarization conditions. A global analysis of the high time-resolution 2D data shows rapid, sub-100 fs energy transfer within the PSII CC. It also reveals the 2D spectral signatures of slower energy equilibration processes occurring on several to hundreds of picosecond time scales that are consistent with previous work. Using a recent structure-based model of the PSII CC [Y. Shibata, S. Nishi, K. Kawakami, J. R. Shen and T. Renger, J. Am. Chem. Soc., 2013, 135, 6903], we simulate the energy transfer in the PSII CC by calculating auxiliary time-resolved fluorescence spectra. We obtain the observed sub-100 fs evolution, even though the calculated electronic energy shows almost no dynamics at early times. On the other hand, the electronic-vibrational interaction energy increases considerably over the same time period. We conclude that interactions with vibrational degrees of freedom not only induce population transfer between the excitonic states in the PSII CC, but also reshape the energy landscape of the system. We suggest that the experimentally observed ultrafast energy transfer is a signature of excitonic-polaron formation.

  2. Interhospital pediatric patient transfers-factors influencing rapid disposition after transfer.

    Science.gov (United States)

    Gattu, Rajender K; Teshome, Getachew; Cai, Ling; Wright, Christian; Lichenstein, Richard

    2014-01-01

    The objective of this study was to determine the incidence, demographics, and clinical course of pediatric patients rapidly discharged after transfer from outlying emergency departments (EDs) to a tertiary care pediatric ED (PED) with no additional diagnostic or therapeutic actions. All pediatric patient charts from July 2009 to June 2010 who were transferred from 31 outlying EDs to an academic PED were reviewed for patient demographics, (age, sex, race) diagnosis, and disposition (admission, discharge). Primary outcome of interest in this study was percentage of children younger than 18 years discharged home after transfer to the tertiary care center (PED) with no additional medical or surgical procedures. Primary outcomes in terms of transferring physician ED pediatric physician versus ED nonpediatric physician (ED-NPP) and transferring hospital type were also analyzed using Fisher exact test. Three hundred forty-two patients transferred from outlying EDs to PED during the study period met inclusion criteria. Sixty percent (207/342) of overall transfers were in the age group 5 years or younger. Respiratory illness (27.5%) was the most common condition in all transfers. Patients transferred from EDs staffed by nonpediatric physician were more likely to be discharged home without needing additional studies or procedures. Patients transferred from EDs staffed by pediatricians were more likely to be admitted or required additional diagnostic and/or therapeutic interventions before disposition. Pediatric patients transferred from outlying community EDs to a PED frequently required little or no additional care. Referring hospital ED type and physician training type are associated with the need for additional workup at the pediatric emergency room.

  3. Interactive Joint Transfer of Energy and Information

    DEFF Research Database (Denmark)

    Popovski, Petar; Fouladgar, A. M.; Simeone, Osvaldo

    2013-01-01

    resources, such as radio waves, particles and qubits, can conceivably reuse, at least part, of the received resources. This paper aims at illustrating some of the new challenges that arise in the design of communication networks in which the signals exchanged by the nodes carry both information and energy......In some communication networks, such as passive RFID systems, the energy used to transfer information between a sender and a recipient can be reused for successive communication tasks. In fact, from known results in physics, any system that exchanges information via the transfer of given physical....... To this end, a baseline two-way communication system is considered in which two nodes communicate in an interactive fashion. In the system, a node can either send an “on” symbol (or “1”), which costs one unit of energy, or an “off” signal (or “0”), which does not require any energy expenditure. Upon reception...

  4. Study made of transfer of heat energy through metal joints in vacuum environment

    Science.gov (United States)

    Elliot, D. H.

    1967-01-01

    Heat energy transfer is concentrated closely around a melted joint and the temperature drop across it decreases rapidly as the bolt and nut are tightened to a minimum torque level. Flat metal surfaces pressed together display a cyclical improvement in heat energy transfer as the interface pressure is increased.

  5. Nonclassical energy transfer in photosynthetic FMO complex

    Directory of Open Access Journals (Sweden)

    Abramavicius Vytautas

    2013-03-01

    Full Text Available Excitation energy transfer in a photosynthetic FMO complex has been simulated using the stochastic Schrödinger equation. Fluctuating chromophore transition energies are simulated from the quantum correlation function which allows to properly include the finite temperature. The resulting excitation dynamics shows fast thermalization of chromophore occupations into proper thermal equilibrium. The relaxation process is characterized by entropy dynamics, which shows nonclassical behavior.

  6. Energy transfer during the hydroentanglement of fibres

    CSIR Research Space (South Africa)

    Moyo, D

    2012-10-01

    Full Text Available , and the resultant degree of fibre entanglement, determines the tensile strength of the nonwoven fabric as a consequence of the inter-fibre friction. Here, the relationship between hydroentangling energy from the waterjets and the changes it brings about... in the nonwoven fabric strength were studied. In the study, the energies of the waterjets transferred to every fabric sample as a function of the waterjet pressure, machine speed, machine efficiency and the web area weight were quantified, and the resultant...

  7. Energy Efficient Storage and Transfer of Cryogens

    Science.gov (United States)

    Fesmire, James E.

    2013-01-01

    Cryogenics is globally linked to energy generation, storage, and usage. Thermal insulation systems research and development is an enabling part of NASA's technology goals for Space Launch and Exploration. New thermal testing methodologies and materials are being transferred to industry for a wide range of commercial applications.

  8. Risk transfer via energy savings insurance

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Evan

    2001-10-01

    Among the key barriers to investment in energy efficiency improvements are uncertainties about attaining projected energy savings and apprehension about potential disputes over these savings. The fields of energy management and risk management are thus intertwined. While many technical methods have emerged to manage performance risks (e.g. building commissioning), financial risk transfer techniques are less developed in the energy management arena than in other more mature segments of the economy. Energy Savings Insurance (ESI) - formal insurance of predicted energy savings - is one method of transferring financial risks away from the facility owner or energy services contractor. ESI offers a number of significant advantages over other forms of financial risk transfer, e.g. savings guarantees or performance bonds. ESI providers manage risk via pre-construction design review as well as post-construction commissioning and measurement and verification of savings. We found that the two mos t common criticisms of ESI - excessive pricing and onerous exclusions - are not born out in practice. In fact, if properly applied, ESI can potentially reduce the net cost of energy savings projects by reducing the interest rates charged by lenders, and by increasing the level of savings through quality control. Debt service can also be ensured by matching loan payments to projected energy savings while designing the insurance mechanism so that payments are made by the insurer in the event of a savings shortfall. We estimate the U.S. ESI market potential of $875 million/year in premium income. From an energy-policy perspective, ESI offers a number of potential benefits: ESI transfers performance risk from the balance sheet of the entity implementing the energy savings project, thereby freeing up capital otherwise needed to ''self-insure'' the savings. ESI reduces barriers to market entry of smaller energy services firms who do not have sufficiently strong balance

  9. Rapid Energy Estimation for Hardware-Software Codesign Using FPGAs

    Directory of Open Access Journals (Sweden)

    Prasanna ViktorK

    2006-01-01

    Full Text Available By allowing parts of the applications to be executed either on soft processors (as software programs or on customized hardware peripherals attached to the processors, FPGAs have made traditional energy estimation techniques inefficient for evaluating various design tradeoffs. In this paper, we propose a high-level simulation-based two-step rapid energy estimation technique for hardware-software codesign using FPGAs. In the first step, a high-level hardware-software cosimulation technique is applied to simulate both the hardware and software components of the target application. High-level simulation results of both software programs running on the processors and the customized hardware peripherals are gathered during the cosimulation process. In the second step, the high-level simulation results of the customized hardware peripherals are used to estimate the switching activities of their corresponding register-transfer/gate level ("low-level" implementations. We use this information to employ an instruction-level energy estimation technique and a domain-specific energy performance modeling technique to estimate the energy dissipation of the complete application. A Matlab/Simulink-based implementation of our approach and two numerical computation applications show that the proposed energy estimation technique can achieve more than 6000x speedup over low-level simulation-based techniques while sacrificing less than 10% estimation accuracy. Compared with the measured results, our experimental results show that the proposed technique achieves an average estimation error of less than 12%.

  10. Energy transfer in structured and unstructured environments

    DEFF Research Database (Denmark)

    Iles-Smith, Jake; Dijkstra, Arend G.; Lambert, Neill

    2016-01-01

    We explore excitonic energy transfer dynamics in a molecular dimer system coupled to both structured and unstructured oscillator environments. By extending the reaction coordinate master equation technique developed by Iles-Smith et al. [Phys. Rev. A 90, 032114 (2014)], we go beyond the commonly...... used Born-Markov approximations to incorporate system-environment correlations and the resultant non-Markovian dynamical effects. We obtain energy transfer dynamics for both underdamped and overdamped oscillator environments that are in perfect agreement with the numerical hierarchical equations...... of motion over a wide range of parameters. Furthermore, we show that the Zusman equations, which may be obtained in a semiclassical limit of the reaction coordinate model, are often incapable of describing the correct dynamical behaviour. This demonstrates the necessity of properly accounting for quantum...

  11. Energy transfer problems of ball lightning

    Energy Technology Data Exchange (ETDEWEB)

    Egely, G.

    1986-04-01

    The paper analyzes the energy transport phenomenon of ball lightnings, but momentum and charge transport phenomena are considered as well. The physical properties as energy density and transfer are investigated using several observers' accounts of interactions with different objects. It is shown that contrary to previous assumptions the ball lightning has negative electric charge, and very high internal energy density. Both internal and external energy source models are analyzed, and it is shown that regardless to the details of a given model neither of them can explain actual observations. This has been validated by a well documented case study, and by several additional observations. An entirely new, testable model is suggested, which is able to stand for all observed properties of ball lightnings, and it explains the cause of rarity of ball lightnings, and the reasons of the unsuccessful experimental efforts. It is shown that the plasma sphere is just a visible side effect of a more important phenomenon.

  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. Energy transfer and kinetics in mechanochemistry.

    Science.gov (United States)

    Chen, Zhiliang; Lu, Shengyong; Mao, Qiongjing; Buekens, Alfons; Wang, Yuting; Yan, Jianhua

    2017-11-01

    Mechanochemistry (MC) exerts extraordinary degradation and decomposition effects on many chlorinated, brominated, and even fluorinated persistent organic pollutants (POPs). However, its application is still limited by inadequate study of its reaction kinetic aspects. In the present work, the ball motion and energy transfer in planetary ball mill are investigated in some detail. Almost all milling parameters are summarised in a single factor-total effective impact energy. Furthermore, the MC kinetic between calcium oxide/Al and hexachlorobenzene is well established and modelled. The results indicate that total effective impact energy and reagent ratio are the two factors sufficient for describing the MC degradation degree of POPs. The reaction rate constant only depends on the chemical properties of reactants, so it could be used as an important index to appraise the quality of MC additives. This model successfully predicts the reaction rate for different operating conditions, indicating that it could be suitably applied for conducting MC reactions in other reactors.

  14. Distributed Wireless Power Transfer With Energy Feedback

    Science.gov (United States)

    Lee, Seunghyun; Zhang, Rui

    2017-04-01

    Energy beamforming (EB) is a key technique for achieving efficient radio-frequency (RF) transmission enabled wireless energy transfer (WET). By optimally designing the waveforms from multiple energy transmitters (ETs) over the wireless channels, they can be constructively combined at the energy receiver (ER) to achieve an EB gain that scales with the number of ETs. However, the optimal design of EB waveforms requires accurate channel state information (CSI) at the ETs, which is challenging to obtain practically, especially in a distributed system with ETs at separate locations. In this paper, we study practical and efficient channel training methods to achieve optimal EB in a distributed WET system. We propose two protocols with and without centralized coordination, respectively, where distributed ETs either sequentially or in parallel adapt their transmit phases based on a low-complexity energy feedback from the ER. The energy feedback only depends on the received power level at the ER, where each feedback indicates one particular transmit phase that results in the maximum harvested power over a set of previously used phases. Simulation results show that the two proposed training protocols converge very fast in practical WET systems even with a large number of distributed ETs, while the protocol with sequential ET phase adaptation is also analytically shown to converge to the optimal EB design with perfect CSI by increasing the training time. Numerical results are also provided to evaluate the performance of the proposed distributed EB and training designs as compared to other benchmark schemes.

  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. 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.

  17. Stochastic Integration H∞ Filter for Rapid Transfer Alignment of INS

    Directory of Open Access Journals (Sweden)

    Dapeng Zhou

    2017-11-01

    Full Text Available The performance of an inertial navigation system (INS operated on a moving base greatly depends on the accuracy of rapid transfer alignment (RTA. However, in practice, the coexistence of large initial attitude errors and uncertain observation noise statistics poses a great challenge for the estimation accuracy of misalignment angles. This study aims to develop a novel robust nonlinear filter, namely the stochastic integration H ∞ filter (SIH ∞ F for improving both the accuracy and robustness of RTA. In this new nonlinear H ∞ filter, the stochastic spherical-radial integration rule is incorporated with the framework of the derivative-free H ∞ filter for the first time, and the resulting SIH ∞ F simultaneously attenuates the negative effect in estimations caused by significant nonlinearity and large uncertainty. Comparisons between the SIH ∞ F and previously well-known methodologies are carried out by means of numerical simulation and a van test. The results demonstrate that the newly-proposed method outperforms the cubature H ∞ filter. Moreover, the SIH ∞ F inherits the benefit of the traditional stochastic integration filter, but with more robustness in the presence of uncertainty.

  18. Low-Energy Ballistic Transfers to Lunar Halo Orbits

    Science.gov (United States)

    Parker, Jeffrey S.

    2009-01-01

    Recent lunar missions have begun to take advantage of the benefits of low-energy ballistic transfers between the Earth and the Moon rather than implementing conventional Hohmann-like lunar transfers. Both Artemis and GRAIL plan to implement low-energy lunar transfers in the next few years. This paper explores the characteristics and potential applications of many different families of low-energy ballistic lunar transfers. The transfers presented here begin from a wide variety of different orbits at the Earth and follow several different distinct pathways to the Moon. This paper characterizes these pathways to identify desirable low-energy lunar transfers for future lunar missions.

  19. Rapid Energy Estimation for Hardware-Software Codesign Using FPGAs

    Directory of Open Access Journals (Sweden)

    Viktor K. Prasanna

    2006-09-01

    Full Text Available By allowing parts of the applications to be executed either on soft processors (as software programs or on customized hardware peripherals attached to the processors, FPGAs have made traditional energy estimation techniques inefficient for evaluating various design tradeoffs. In this paper, we propose a high-level simulation-based two-step rapid energy estimation technique for hardware-software codesign using FPGAs. In the first step, a high-level hardware-software cosimulation technique is applied to simulate both the hardware and software components of the target application. High-level simulation results of both software programs running on the processors and the customized hardware peripherals are gathered during the cosimulation process. In the second step, the high-level simulation results of the customized hardware peripherals are used to estimate the switching activities of their corresponding register-transfer/gate level (“low-level” implementations. We use this information to employ an instruction-level energy estimation technique and a domain-specific energy performance modeling technique to estimate the energy dissipation of the complete application. A Matlab/Simulink-based implementation of our approach and two numerical computation applications show that the proposed energy estimation technique can achieve more than 6000x speedup over low-level simulation-based techniques while sacrificing less than 10% estimation accuracy. Compared with the measured results, our experimental results show that the proposed technique achieves an average estimation error of less than 12%.

  20. Enhancing radiative energy transfer through thermal extraction

    Science.gov (United States)

    Tan, Yixuan; Liu, Baoan; Shen, Sheng; Yu, Zongfu

    2016-06-01

    Thermal radiation plays an increasingly important role in many emerging energy technologies, such as thermophotovoltaics, passive radiative cooling and wearable cooling clothes [1]. One of the fundamental constraints in thermal radiation is the Stefan-Boltzmann law, which limits the maximum power of far-field radiation to P0 = σT4S, where σ is the Boltzmann constant, S and T are the area and the temperature of the emitter, respectively (Fig. 1a). In order to overcome this limit, it has been shown that near-field radiations could have an energy density that is orders of magnitude greater than the Stefan-Boltzmann law [2-7]. Unfortunately, such near-field radiation transfer is spatially confined and cannot carry radiative heat to the far field. Recently, a new concept of thermal extraction was proposed [8] to enhance far-field thermal emission, which, conceptually, operates on a principle similar to oil immersion lenses and light extraction in light-emitting diodes using solid immersion lens to increase light output [62].Thermal extraction allows a blackbody to radiate more energy to the far field than the apparent limit of the Stefan-Boltzmann law without breaking the second law of thermodynamics. Thermal extraction works by using a specially designed thermal extractor to convert and guide the near-field energy to the far field, as shown in Fig. 1b. The same blackbody as shown in Fig. 1a is placed closely below the thermal extractor with a spacing smaller than the thermal wavelength. The near-field coupling transfers radiative energy with a density greater than σT4. The thermal extractor, made from transparent and high-index or structured materials, does not emit or absorb any radiation. It transforms the near-field energy and sends it toward the far field. As a result, the total amount of far-field radiative heat dissipated by the same blackbody is greatly enhanced above SσT4, where S is the area of the emitter. This paper will review the progress in thermal

  1. Enhancing radiative energy transfer through thermal extraction

    Directory of Open Access Journals (Sweden)

    Tan Yixuan

    2016-06-01

    Full Text Available Thermal radiation plays an increasingly important role in many emerging energy technologies, such as thermophotovoltaics, passive radiative cooling and wearable cooling clothes [1]. One of the fundamental constraints in thermal radiation is the Stefan-Boltzmann law, which limits the maximum power of far-field radiation to P0 = σT4S, where σ is the Boltzmann constant, S and T are the area and the temperature of the emitter, respectively (Fig. 1a. In order to overcome this limit, it has been shown that near-field radiations could have an energy density that is orders of magnitude greater than the Stefan-Boltzmann law [2-7]. Unfortunately, such near-field radiation transfer is spatially confined and cannot carry radiative heat to the far field. Recently, a new concept of thermal extraction was proposed [8] to enhance far-field thermal emission, which, conceptually, operates on a principle similar to oil immersion lenses and light extraction in light-emitting diodes using solid immersion lens to increase light output [62].Thermal extraction allows a blackbody to radiate more energy to the far field than the apparent limit of the Stefan-Boltzmann law without breaking the second law of thermodynamics.

  2. Nanophotonics: Energy Transfer towards Enhanced Luminescent Chemosensing

    Directory of Open Access Journals (Sweden)

    Roy Aad

    2015-04-01

    Full Text Available We discuss a recently proposed novel photonic approach for enhancing the fluorescence of extremely thin chemosensing polymer layers. We present theoretical and experimental results demonstrating the concept of gain-assisted waveguided energy transfer (G-WET on a very thin polymer nanolayer spincoated on an active ZnO thin film. The G-WET approach is shown to result in an 8-fold increase in polymer fluorescence. We then extend the G-WET concept to nanostructured media. The benefits of using active nanostructured substrates on the sensitivity and fluorescence of chemosensing polymers are discussed. Preliminary theoretical results on enlarged sensing surface and photonic band-gap are presented.

  3. Rapid prototyping of energy management charging strategies

    Energy Technology Data Exchange (ETDEWEB)

    Ciulavu, Oana [Hella Electronics Romania, Timisoara (Romania); Starkmuth, Timo; Jesolowitz, Reinhard [Hella KGaA Hueck und Co., Lippstadt (Germany)

    2010-07-01

    This paper presents an approach to develop charging strategies to support a vehicle energy management aiming for the reduction of CO{sub 2} emissions and decreased fuel consumption by using the Hardware-in-the-loop (HIL) environment. (orig.)

  4. Kinetic energy transfer during the tennis serve

    Directory of Open Access Journals (Sweden)

    C.L. de Subijana

    2010-12-01

    Full Text Available Several studies have established the pattern used in the over arm hitting and throwing movements, however to date there has not been one which statistically expresses the Kinetic Link Principle of the tennis serve. The main goals of this study were: first to investigate the kinetic energy transmission pattern using a complete mechanical body model and second, to create a tool which could help evaluating the individual technique of a tennis player. This tool was a statistical procedure which expressed the individual technique of a player as a mathematical function. Fourteen and twelve flat tennis serves of two top tennis players landing in an aiming area were recorded with two synchronized video cameras at 125 Hz. The experimental technique was 3D photogrammetry. A 28 points body model with five solid-rigid (the pelvis, the thorax, the upper arms and the racquet was built. The kinetic energies from the body segments were considered the biomechanical parameters. The mean speeds of the balls were 41.9 m/s (150.9 km/hr and 38.1 m/s (137.2 km/hr. A Kinetic Sequential Action Muscle principle based on the kinetic energy transfer was probed statistically by mean a correlation analysis [3]. This pattern showed the existence of a proximal to distal sequence of kinetic energy maximums. A significant (p<0.05 discriminant function for each player could predict the category of the serve (“good” or “bad” in the 78.6% and 100% of the cases. This function facilitated the understanding of the individual technique of a tennis player showing that this could be a tool for the tennis training complementary to the qualitative (observational analysis.

  5. Well-defined critical association concentration and rapid adsorption at the air/water interface of a short amphiphilic polymer, amphipol A8-35: a study by Förster resonance energy transfer and dynamic surface tension measurements.

    Science.gov (United States)

    Giusti, Fabrice; Popot, Jean-Luc; Tribet, Christophe

    2012-07-17

    Amphipols (APols) are short amphiphilic polymers designed to handle membrane proteins (MPs) in aqueous solutions as an alternative to small surfactants (detergents). APols adsorb onto the transmembrane, hydrophobic surface of MPs, forming small, water-soluble complexes, in which the protein is biochemically stabilized. At variance with MP/detergent complexes, MP/APol ones remain stable even at extreme dilutions. Pure APol solutions self-associate into well-defined micelle-like globules comprising a few APol molecules, a rather unusual behavior for amphiphilic polymers, which typically form ill-defined assemblies. The best characterized APol to date, A8-35, is a random copolymer of acrylic acid, isopropylacrylamide, and octylacrylamide. In the present work, the concentration threshold for self-association of A8-35 in salty buffer (NaCl 100 mM, Tris/HCl 20 mM, pH 8.0) has been studied by Förster resonance energy transfer (FRET) measurements and tensiometry. In a 1:1 mol/mol mixture of APols grafted with either rhodamine or 7-nitro-1,2,3-benzoxadiazole, the FRET signal as a function of A8-35 concentration is essentially zero below a threshold concentration of 0.002 g·L(-1) and increases linearly with concentration above this threshold. This indicates that assembly takes place in a narrow concentration interval around 0.002 g·L(-1). Surface tension measurements decreases regularly with concentration until a threshold of ca. 0.004 g·L(-1), beyond which it reaches a plateau at ca. 30 mN·m(-1). Within experimental uncertainties, the two techniques thus yield a comparable estimate of the critical self-assembly concentration. The kinetics of variation of the surface tension was analyzed by dynamic surface tension measurements in the time window 10 ms-100 s. The rate of surface tension decrease was similar in solutions of A8-35 and of the anionic surfactant sodium dodecylsulfate when both compounds were at a similar molar concentration of n-alkyl moieties. Overall, the

  6. Energy transfer between a nanosystem and its host fluid: A multiscale factorization approach

    Science.gov (United States)

    Sereda, Yuriy V.; Espinosa-Duran, John M.; Ortoleva, Peter J.

    2014-02-01

    Energy transfer between a macromolecule or supramolecular assembly and a host medium is considered from the perspective of Newton's equations and Lie-Trotter factorization. The development starts by demonstrating that the energy of the molecule evolves slowly relative to the time scale of atomic collisions-vibrations. The energy is envisioned to be a coarse-grained variable that coevolves with the rapidly fluctuating atomistic degrees of freedom. Lie-Trotter factorization is shown to be a natural framework for expressing this coevolution. A mathematical formalism and workflow for efficient multiscale simulation of energy transfer is presented. Lactoferrin and human papilloma virus capsid-like structure are used for validation.

  7. The security energy encryption in wireless power transfer

    Science.gov (United States)

    Sadzali, M. N.; Ali, A.; Azizan, M. M.; Albreem, M. A. M.

    2017-09-01

    This paper presents a concept of security in wireless power transfer (WPT) by applying chaos theory. Chaos theory is applied as a security system in order to safeguard the transfer of energy from a transmitter to the intended receiver. The energy encryption of the wireless power transfer utilizes chaos theory to generate the possibility of a logistic map for the chaotic security key. The simulation for energy encryption wireless power transfer system was conducted by using MATLAB and Simulink. By employing chaos theory, the chaotic key ensures the transmission of energy from transmitter to its intended receiver.

  8. Integrated analysis of energy transfers in elastic-wave turbulence.

    Science.gov (United States)

    Yokoyama, Naoto; Takaoka, Masanori

    2017-08-01

    In elastic-wave turbulence, strong turbulence appears in small wave numbers while weak turbulence does in large wave numbers. Energy transfers in the coexistence of these turbulent states are numerically investigated in both the Fourier space and the real space. An analytical expression of a detailed energy balance reveals from which mode to which mode energy is transferred in the triad interaction. Stretching energy excited by external force is transferred nonlocally and intermittently to large wave numbers as the kinetic energy in the strong turbulence. In the weak turbulence, the resonant interactions according to the weak turbulence theory produce cascading net energy transfer to large wave numbers. Because the system's nonlinearity shows strong temporal intermittency, the energy transfers are investigated at active and moderate phases separately. The nonlocal interactions in the Fourier space are characterized by the intermittent bundles of fibrous structures in the real space.

  9. High resolution IR diode laser study of collisional energy transfer between highly vibrationally excited monofluorobenzene and CO2: the effect of donor fluorination on strong collision energy transfer.

    Science.gov (United States)

    Kim, Kilyoung; Johnson, Alan M; Powell, Amber L; Mitchell, Deborah G; Sevy, Eric T

    2014-12-21

    Collisional energy transfer between vibrational ground state CO2 and highly vibrationally excited monofluorobenzene (MFB) was studied using narrow bandwidth (0.0003 cm(-1)) IR diode laser absorption spectroscopy. Highly vibrationally excited MFB with E' = ∼41,000 cm(-1) was prepared by 248 nm UV excitation followed by rapid radiationless internal conversion to the electronic ground state (S1→S0*). The amount of vibrational energy transferred from hot MFB into rotations and translations of CO2 via collisions was measured by probing the scattered CO2 using the IR diode laser. The absolute state specific energy transfer rate constants and scattering probabilities for single collisions between hot MFB and CO2 were measured and used to determine the energy transfer probability distribution function, P(E,E'), in the large ΔE region. P(E,E') was then fit to a bi-exponential function and extrapolated to the low ΔE region. P(E,E') and the biexponential fit data were used to determine the partitioning between weak and strong collisions as well as investigate molecular properties responsible for large collisional energy transfer events. Fermi's Golden rule was used to model the shape of P(E,E') and identify which donor vibrational motions are primarily responsible for energy transfer. In general, the results suggest that low-frequency MFB vibrational modes are primarily responsible for strong collisions, and govern the shape and magnitude of P(E,E'). Where deviations from this general trend occur, vibrational modes with large negative anharmonicity constants are more efficient energy gateways than modes with similar frequency, while vibrational modes with large positive anharmonicity constants are less efficient at energy transfer than modes of similar frequency.

  10. Energy transfer in erbium doped optical waveguides based on silicon

    NARCIS (Netherlands)

    Kik, Pieter Geert

    2000-01-01

    Energy transfer in erbium doped optical waveguides based on silicon This thesis describes the energy transfer processes occurring in materials that can be used for the fabrication of silicon compatible optical integrated circuits, operating at 1.54 mm.The thesis consists of three parts: Part I

  11. Ultrafast Energy Transfer in an Artificial Photosynthetic Antenna

    Directory of Open Access Journals (Sweden)

    van Grondelle R.

    2013-03-01

    Full Text Available We temporally resolved energy transfer kinetics in an artificial light-harvesting dyad composed of a phthalocyanine covalently linked to a carotenoid. Upon carotenoid photo-excitation, energy transfers within ≈100fs (≈52% efficiency to the phthalocyanine.

  12. Mode-to-mode energy transfers in convective patterns

    Indian Academy of Sciences (India)

    Abstract. We investigate the energy transfer between various Fourier modes in a low- dimensional model for thermal convection. We have used the formalism of mode-to-mode energy transfer rate in our calculation. The evolution equations derived using this scheme is the same as those derived using the hydrodynamical ...

  13. Significance of a Recurring Function in Energy Transfer

    Science.gov (United States)

    Mishra, Subodha

    2017-01-01

    The appearance of a unique function in the energy transfer from one system to the other in different physical situations such as electrical, mechanical, optical, and quantum mechanical processes is established in this work. Though the laws governing the energy transformation and its transfer from system to system are well known, here we notice a…

  14. Detection of three porcine vesicular viruses using multiplex real-time primer-probe energy transfer

    DEFF Research Database (Denmark)

    Rasmussen, Thomas Bruun; Uttenthal, Åse; Aguero, M.

    2006-01-01

    Rapid identification of the etiologic agent in infected animals is important for the control of an outbreak of vesicular disease in livestock. We have in the present study developed a multiplex real-time reverse transcription-PCR, based on primer-probe energy transfer (PriProET), for simultaneous...

  15. Visual prosthesis wireless energy transfer system optimal modeling.

    Science.gov (United States)

    Li, Xueping; Yang, Yuan; Gao, Yong

    2014-01-16

    Wireless energy transfer system is an effective way to solve the visual prosthesis energy supply problems, theoretical modeling of the system is the prerequisite to do optimal energy transfer system design. On the basis of the ideal model of the wireless energy transfer system, according to visual prosthesis application condition, the system modeling is optimized. During the optimal modeling, taking planar spiral coils as the coupling devices between energy transmitter and receiver, the effect of the parasitic capacitance of the transfer coil is considered, and especially the concept of biological capacitance is proposed to consider the influence of biological tissue on the energy transfer efficiency, resulting in the optimal modeling's more accuracy for the actual application. The simulation data of the optimal model in this paper is compared with that of the previous ideal model, the results show that under high frequency condition, the parasitic capacitance of inductance and biological capacitance considered in the optimal model could have great impact on the wireless energy transfer system. The further comparison with the experimental data verifies the validity and accuracy of the optimal model proposed in this paper. The optimal model proposed in this paper has a higher theoretical guiding significance for the wireless energy transfer system's further research, and provide a more precise model reference for solving the power supply problem in visual prosthesis clinical application.

  16. Rapid heteroatom transfer to arylmetals utilizing multifunctional reagent scaffolds

    Science.gov (United States)

    Gao, Hongyin; Zhou, Zhe; Kwon, Doo-Hyun; Coombs, James; Jones, Steven; Behnke, Nicole Erin; Ess, Daniel H.; Kürti, László

    2017-07-01

    Arylmetals are highly valuable carbon nucleophiles that are readily and inexpensively prepared from aryl halides or arenes and widely used on both laboratory and industrial scales to react directly with a wide range of electrophiles. Although C-C bond formation has been a staple of organic synthesis, the direct transfer of primary amino (-NH2) and hydroxyl (-OH) groups to arylmetals in a scalable and environmentally friendly fashion remains a formidable synthetic challenge because of the absence of suitable heteroatom-transfer reagents. Here, we demonstrate the use of bench-stable N-H and N-alkyl oxaziridines derived from readily available terpenoid scaffolds as efficient multifunctional reagents for the direct primary amination and hydroxylation of structurally diverse aryl- and heteroarylmetals. This practical and scalable method provides one-step synthetic access to primary anilines and phenols at low temperature and avoids the use of transition-metal catalysts, ligands and additives, nitrogen-protecting groups, excess reagents and harsh workup conditions.

  17. The Grover energy transfer algorithm for relativistic speeds

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Escartin, Juan Carlos; Chamorro-Posada, Pedro, E-mail: juagar@yllera.tel.uva.e [Dpto. de TeorIa de la Senal y Comunicaciones e Ingenieria Telematica, Universidad de Valladolid, ETSI de Telecomunicacion, Campus Miguel Delibes, Paseo Belen 15, 47011 Valladolid (Spain)

    2010-11-12

    Grover's algorithm for quantum search can also be applied to classical energy transfer. The procedure takes a system in which the total energy is equally distributed among N subsystems and transfers most of it to one marked subsystem. We show that in a relativistic setting the efficiency of this procedure can be improved. We will consider the transfer of relativistic kinetic energy in a series of elastic collisions. In this case, the number of steps of the energy transfer procedure approaches 1 as the initial velocities of the objects become closer to the speed of light. This is a consequence of introducing nonlinearities in the procedure. However, the maximum attainable transfer will depend on the particular combination of speed and number of objects. In the procedure, we will use N elements, as in the classical non-relativistic case, instead of the log{sub 2}(N) states of the quantum algorithm.

  18. Energy considerations in accelerating rapid shear granular flows

    Directory of Open Access Journals (Sweden)

    S. P. Pudasaini

    2009-05-01

    Full Text Available We present a complete expression for the total energy associated with a rapid frictional granular shear flow down an inclined surface. This expression reduces to the often used energy for a non-accelerating flow of an isotropic, ideal fluid in a horizontal channel, or to the energy for a vertically falling mass. We utilize thickness-averaged mass and momentum conservation laws written in a slope-defined coordinate system. Both the enhanced gravity and friction are taken into account in addition to the bulk motion and deformation. The total energy of the flow at a given spatial position and time is defined as the sum of four energy components: the kinetic energy, gravity, pressure and the friction energy. Total energy is conserved for stationary flow, but for non-stationary flow the non-conservative force induced by the free-surface gradient means that energy is not conserved. Simulations and experimental results are used to sketch the total energy of non-stationary flows. Comparison between the total energy and the sum of the kinetic and pressure energy shows that the contribution due to gravity acceleration and frictional resistance can be of the same order of magnitude, and that the geometric deformation plays an important role in the total energy budget of the cascading mass. Relative importance of the different constituents in the total energy expression is explored. We also introduce an extended Froude number that takes into account the apparent potential energy induced by gravity and pressure.

  19. Pair transfer processes probed at deep sub barrier energies

    Directory of Open Access Journals (Sweden)

    Scarlassara F.

    2011-10-01

    Full Text Available Multinucleon transfer cross sections in the system 40Ca+96Zr have been measured at bombarding energies ranging from the Coulomb barrier to ~ 25% below. Target-like (lighter recoils in inverse kinematics have been completely identif ed in A,Z and Q-value with the large solid angle magnetic spectrometer PRISMA. The experimental slopes of the neutron transfer probabilities at large internuclear separation are consistent with the values derived from the binding energies. A phenomenological interpretation of the transfer probabilities indicates the presence of enhanced values for the even number of neutron transfers.

  20. Geo energy research and development: technology transfer update

    Energy Technology Data Exchange (ETDEWEB)

    Traeger, R.K.; Dugan, V.L.

    1983-01-01

    Sandia Geo Energy Programs in geothermal, coal, oil and gas, and synfuel technologies have been effective in transferring research concepts to applications in private industry. This report updates the previous summary (SAND82-0211, March 1982) to include recent technology transfers and to reflect recent changes in philosophy on technology transfer. Over 40 items transferred to industry have been identified in the areas of Hardware, Risk Removal and Understanding. Successful transfer is due largely to personal interactions between Sandia engineers and the technical staffs of private industry.

  1. A planning framework for transferring building energy technologies

    Energy Technology Data Exchange (ETDEWEB)

    Farhar, B C; Brown, M A; Mohler, B L; Wilde, M; Abel, F H

    1990-07-01

    Accelerating the adoption of new and existing cost-effective technologies has significant potential to reduce the energy consumed in US buildings. This report presents key results of an interlaboratory technology transfer planning effort in support of the US Department of Energy's Office of Building Technologies (OBT). A guiding assumption for planning was that OBT's R D program should forge linkages with existing programs whose goals involved enhancing energy efficiency in buildings. An ad hoc Technology Transfer Advisory Group reviewed the existing analysis and technology transfer program, brainstormed technology transfer approaches, interviewed DOE program managers, identified applicable research results, and developed a framework that management could use in deciding on the best investments of technology transfer resources. Representatives of 22 organizations were interviewed on their views of the potential for transferring energy efficiency technologies through active linking with OBT. The report describes these programs and interview results; outlines OBT tools, technologies, and practices to be transferred; defines OBT audiences; identifies technology transfer functions and presents a framework devised using functions and audiences; presents some 60 example technology transfer activities; and documents the Advisory Group's recommendations. 37 refs., 3 figs., 12 tabs.

  2. Anomalous surplus energy transfer observed with multiple FRET acceptors.

    Directory of Open Access Journals (Sweden)

    Srinagesh V Koushik

    2009-11-01

    Full Text Available Förster resonance energy transfer (FRET is a mechanism where energy is transferred from an excited donor fluorophore to adjacent chromophores via non-radiative dipole-dipole interactions. FRET theory primarily considers the interactions of a single donor-acceptor pair. Unfortunately, it is rarely known if only a single acceptor is present in a molecular complex. Thus, the use of FRET as a tool for measuring protein-protein interactions inside living cells requires an understanding of how FRET changes with multiple acceptors. When multiple FRET acceptors are present it is assumed that a quantum of energy is either released from the donor, or transferred in toto to only one of the acceptors present. The rate of energy transfer between the donor and a specific acceptor (k(D-->A can be measured in the absence of other acceptors, and these individual FRET transfer rates can be used to predict the ensemble FRET efficiency using a simple kinetic model where the sum of all FRET transfer rates is divided by the sum of all radiative and non-radiative transfer rates.The generality of this approach was tested by measuring the ensemble FRET efficiency in two constructs, each containing a single fluorescent-protein donor (Cerulean and either two or three FRET acceptors (Venus. FRET transfer rates between individual donor-acceptor pairs within these constructs were calculated from FRET efficiencies measured after systematically introducing point mutations to eliminate all other acceptors. We find that the amount of energy transfer observed in constructs having multiple acceptors is significantly greater than the FRET efficiency predicted from the sum of the individual donor to acceptor transfer rates.We conclude that either an additional energy transfer pathway exists when multiple acceptors are present, or that a theoretical assumption on which the kinetic model prediction is based is incorrect.

  3. Excitation energy transfer in isolated chlorosomes from Chloroflexus aurantiacus

    Science.gov (United States)

    Martiskainen, Jari; Linnanto, Juha; Kananavičius, Robertas; Lehtovuori, Viivi; Korppi-Tommola, Jouko

    2009-07-01

    Chlorosomes from green photosynthetic bacteria Chloroflexus aurantiacus have been studied by time-resolved femtosecond transient absorption spectroscopy. The fastest kinetics of 200-300 fs resolved, was interpreted to stem for intra-chlorosomal excitation energy transfer. Energy transfer from the antenna to the baseplate appeared as a major 9.2 ps rise component detected at the baseplate probe wavelength. Excitation energy transfer rates were evaluated for a model chlorosome. Calculated rod to rod, and rods to baseplate rate constants of 200-400 fs and 10-20 ps, respectively, are in accord with the experimental results.

  4. Energy efficient building design. A transfer guide for local governments

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

    The fundamental concepts of the building design process, energy codes and standards, and energy budgets are introduced. These tools were combined into Energy Design Guidelines and design contract requirements. The Guidelines were repackaged for a national audience and a videotape for selling the concept to government executives. An effort to test transfer of the Guidelines to outside agencies is described.

  5. INTRAMOLECULAR CHARGE AND ENERGY TRANSFER IN MULTICHROMOPHORIC AROMATIC SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Edward C. Lim

    2008-09-09

    A concerted experimental and computational study of energy transfer in nucleic acid bases and charge transfer in dialkylaminobenzonitriles, and related electron donor-acceptor molecules, indicate that the ultrafast photoprocesses occur through three-state conical interactions involving an intermediate state of biradical character.

  6. Fluorescence and Intramolecular Energy Transfer in Polyphenylene Dendrimers

    NARCIS (Netherlands)

    Liu, Daojun; Feyter, Steven De; Cotlet, Mircea; Stefan, Alina; Wiesler, Uwe-Martin; Herrmann, Andreas; Grebel-Koehler, Dörthe; Qu, Jianqiang; Müllen, Klaus; Schryver, Frans C. De

    2003-01-01

    The fluorescence of polyphenylene dendrimers and the intramolecular energy transfer in polyphenylene dendrimers containing a perylenediimide core have been investigated in this paper. Polyphenylene dendrimers composed of tens or hundreds of out-of-plane twisted phenyl units exhibit strong

  7. Energy transfers and magnetic energy growth in small-scale dynamo

    KAUST Repository

    Kumar, Rohit Raj

    2013-12-01

    In this letter we investigate the dynamics of magnetic energy growth in small-scale dynamo by studying energy transfers, mainly energy fluxes and shell-to-shell energy transfers. We perform dynamo simulations for the magnetic Prandtl number Pm = 20 on 10243 grid using the pseudospectral method. We demonstrate that the magnetic energy growth is caused by nonlocal energy transfers from the large-scale or forcing-scale velocity field to small-scale magnetic field. The peak of these energy transfers moves towards lower wave numbers as dynamo evolves, which is the reason why the integral scale of the magnetic field increases with time. The energy transfers U2U (velocity to velocity) and B2B (magnetic to magnetic) are forward and local. Copyright © EPLA, 2013.

  8. Modelling excitonic-energy transfer in light-harvesting complexes

    OpenAIRE

    Kramer, Tobias; Kreisbeck, Christoph

    2013-01-01

    The theoretical and experimental study of energy transfer in photosynthesis has revealed an interesting transport regime, which lies at the borderline between classical transport dynamics and quantum-mechanical interference effects. Dissipation is caused by the coupling of electronic degrees of freedom to vibrational modes and leads to a directional energy transfer from the antenna complex to the target reaction-center. The dissipative driving is robust and does not rely on fine-tuning of spe...

  9. On Kinetics Modeling of Vibrational Energy Transfer

    Science.gov (United States)

    Gilmore, John O.; Sharma, Surendra P.; Cavolowsky, John A. (Technical Monitor)

    1996-01-01

    Two models of vibrational energy exchange are compared at equilibrium to the elementary vibrational exchange reaction for a binary mixture. The first model, non-linear in the species vibrational energies, was derived by Schwartz, Slawsky, and Herzfeld (SSH) by considering the detailed kinetics of vibrational energy levels. This model recovers the result demanded at equilibrium by the elementary reaction. The second model is more recent, and is gaining use in certain areas of computational fluid dynamics. This model, linear in the species vibrational energies, is shown not to recover the required equilibrium result. Further, this more recent model is inconsistent with its suggested rate constants in that those rate constants were inferred from measurements by using the SSH model to reduce the data. The non-linear versus linear nature of these two models can lead to significant differences in vibrational energy coupling. Use of the contemporary model may lead to significant misconceptions, especially when integrated in computer codes considering multiple energy coupling mechanisms.

  10. Dependence of the energy transfer to graphene on the excitation energy

    Energy Technology Data Exchange (ETDEWEB)

    Mackowski, Sebastian, E-mail: mackowski@fizyka.umk.pl; Kamińska, Izabela [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland)

    2015-07-13

    Fluorescence studies of natural photosynthetic complexes on a graphene layer demonstrate pronounced influence of the excitation wavelength on the energy transfer efficiency to graphene. Ultraviolet light yields much faster decay of fluorescence, with average efficiencies of the energy transfer equal to 87% and 65% for excitation at 405 nm and 640 nm, respectively. This implies that focused light changes locally the properties of graphene affecting the energy transfer dynamics, in an analogous way as in the case of metallic nanostructures. Demonstrating optical control of the energy transfer is important for exploiting unique properties of graphene in photonic and sensing architectures.

  11. Energy transfers in dynamos with small magnetic Prandtl numbers

    KAUST Repository

    Kumar, Rohit

    2015-06-25

    We perform numerical simulation of dynamo with magnetic Prandtl number Pm = 0.2 on 10243 grid, and compute the energy fluxes and the shell-to-shell energy transfers. These computations indicate that the magnetic energy growth takes place mainly due to the energy transfers from large-scale velocity field to large-scale magnetic field and that the magnetic energy flux is forward. The steady-state magnetic energy is much smaller than the kinetic energy, rather than equipartition; this is because the magnetic Reynolds number is near the dynamo transition regime. We also contrast our results with those for dynamo with Pm = 20 and decaying dynamo. © 2015 Taylor & Francis.

  12. Energy transfer in scattering by rotating potentials

    Indian Academy of Sciences (India)

    Quantum mechanical scattering theory is studied for time-dependent Schrödinger operators, in particular for particles in a rotating potential. Under various assumptions about the decay rate at infinity we show uniform boundedness in time for the kinetic energy of scattering states, existence and completeness of wave ...

  13. The feasibility of coherent energy transfer in microtubules.

    Science.gov (United States)

    Craddock, Travis John Adrian; Friesen, Douglas; Mane, Jonathan; Hameroff, Stuart; Tuszynski, Jack A

    2014-11-06

    It was once purported that biological systems were far too 'warm and wet' to support quantum phenomena mainly owing to thermal effects disrupting quantum coherence. However, recent experimental results and theoretical analyses have shown that thermal energy may assist, rather than disrupt, quantum coherent transport, especially in the 'dry' hydrophobic interiors of biomolecules. Specifically, evidence has been accumulating for the necessary involvement of quantum coherent energy transfer between uniquely arranged chromophores in light harvesting photosynthetic complexes. The 'tubulin' subunit proteins, which comprise microtubules, also possess a distinct architecture of chromophores, namely aromatic amino acids, including tryptophan. The geometry and dipolar properties of these aromatics are similar to those found in photosynthetic units indicating that tubulin may support coherent energy transfer. Tubulin aggregated into microtubule geometric lattices may support such energy transfer, which could be important for biological signalling and communication essential to living processes. Here, we perform a computational investigation of energy transfer between chromophoric amino acids in tubulin via dipole excitations coupled to the surrounding thermal environment. We present the spatial structure and energetic properties of the tryptophan residues in the microtubule constituent protein tubulin. Plausibility arguments for the conditions favouring a quantum mechanism of signal propagation along a microtubule are provided. Overall, we find that coherent energy transfer in tubulin and microtubules is biologically feasible. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  14. Energy transfer process of anisothermal wall-bounded flows

    Energy Technology Data Exchange (ETDEWEB)

    Aulery, Frédéric, E-mail: frederic.aulery@gmail.com [PROMES CNRS – UPR 8521, Rambla de la Thermodynamique, Tecnosud, Perpignan (France); Toutant, Adrien [PROMES CNRS – UPR 8521, Rambla de la Thermodynamique, Tecnosud, Perpignan (France); Université de Perpignan Via Domitia, 52 avenue Paul Alduy, 66860 Perpignan Cedex 9 (France); Bataille, Françoise [PROMES CNRS – UPR 8521, Rambla de la Thermodynamique, Tecnosud, Perpignan (France); Florida State University, Department of Mathematics, Tallahassee, FL (United States); Zhou, Ye, E-mail: zhou3@llnl.gov [Lawrence Livermore National Laboratory, Livermore, CA (United States)

    2015-07-31

    Strong temperature gradients introduce a major external agency into the wall-bounded turbulent flows. In these flows, the temperature field and the turbulent velocity field are highly correlated. In fact, standard RANS turbulent models are not able to accurately reproduce these flows. In order to improve the performance of the models, we need to understand how the energy is produced, transferred, and dissipated in a strong anisothermal wall-bounded flow. This letter presents a first detailed investigation on the roles played by each contributor in the energy transfer equation. - Highlights: • Turbulent flows subject to high temperature gradients are considered. • The influence of the “temperature gradients” on the energy transfer process is determined. • Inverse energy cascade in an anisotropic flow is observed.

  15. High power free space optical link for rapid energy and data transmission

    Science.gov (United States)

    Dhadwal, Harbans S.; Rastegar, Jahangir; Feng, Dake; Kwok, Philip

    2016-05-01

    Design and experimental data for a high power laser diode based free space point-to-point optical power/data link is presented. In time critical power up applications, such as providing power and guidance information to a munition shell just prior to deployment, energy of the order of 100 J needs to be transferred in under 10 s. Current inductive technology is slow and broadcasts a radio-frequency signal which is undesirable for stealth operation. Rapid energy transfer times require high irradiance levels at the surface of the photovoltaic cells, typically, exceeding 1000X suns. Through efficient thermal design of heat sinks, high optical to electrical power conversion efficiencies of 50%, which are usually attainable at low power levels of 1 W, are achievable at higher power levels.

  16. Production and transfer of energy and information in Hamiltonian systems.

    Science.gov (United States)

    Antonopoulos, Chris G; Bianco-Martinez, Ezequiel; Baptista, Murilo S

    2014-01-01

    We present novel results that relate energy and information transfer with sensitivity to initial conditions in chaotic multi-dimensional Hamiltonian systems. We show the relation among Kolmogorov-Sinai entropy, Lyapunov exponents, and upper bounds for the Mutual Information Rate calculated in the Hamiltonian phase space and on bi-dimensional subspaces. Our main result is that the net amount of transfer from kinetic to potential energy per unit of time is a power-law of the upper bound for the Mutual Information Rate between kinetic and potential energies, and also a power-law of the Kolmogorov-Sinai entropy. Therefore, transfer of energy is related with both transfer and production of information. However, the power-law nature of this relation means that a small increment of energy transferred leads to a relatively much larger increase of the information exchanged. Then, we propose an "experimental" implementation of a 1-dimensional communication channel based on a Hamiltonian system, and calculate the actual rate with which information is exchanged between the first and last particle of the channel. Finally, a relation between our results and important quantities of thermodynamics is presented.

  17. Production and transfer of energy and information in Hamiltonian systems.

    Directory of Open Access Journals (Sweden)

    Chris G Antonopoulos

    Full Text Available We present novel results that relate energy and information transfer with sensitivity to initial conditions in chaotic multi-dimensional Hamiltonian systems. We show the relation among Kolmogorov-Sinai entropy, Lyapunov exponents, and upper bounds for the Mutual Information Rate calculated in the Hamiltonian phase space and on bi-dimensional subspaces. Our main result is that the net amount of transfer from kinetic to potential energy per unit of time is a power-law of the upper bound for the Mutual Information Rate between kinetic and potential energies, and also a power-law of the Kolmogorov-Sinai entropy. Therefore, transfer of energy is related with both transfer and production of information. However, the power-law nature of this relation means that a small increment of energy transferred leads to a relatively much larger increase of the information exchanged. Then, we propose an "experimental" implementation of a 1-dimensional communication channel based on a Hamiltonian system, and calculate the actual rate with which information is exchanged between the first and last particle of the channel. Finally, a relation between our results and important quantities of thermodynamics is presented.

  18. 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.

  19. TRANSFER

    African Journals Online (AJOL)

    Abstract. Quenching of curcumine fluorescence by thionine, both immobilised in cellulose acetate occurs in accordance with the Forster mechanism of energy transfer. The rate constant of energy transfer for this donor - acceptor pair is found to be 9.4 x 109 L ' mol S1 with R0 = 37±1 Б. When this donor - acceptor pair is ...

  20. Using Multiple Schedules during Functional Communication Training to Promote Rapid Transfer of Treatment Effects

    Science.gov (United States)

    Fisher, Wayne W.; Greer, Brian D.; Fuhrman, Ashley M.; Querim, Angie C.

    2015-01-01

    Multiple schedules with signaled periods of reinforcement and extinction have been used to thin reinforcement schedules during functional communication training (FCT) to make the intervention more practical for parents and teachers. We evaluated whether these signals would also facilitate rapid transfer of treatment effects across settings and…

  1. Energy transfer between a nanosystem and its host fluid: A multiscale factorization approach

    Energy Technology Data Exchange (ETDEWEB)

    Sereda, Yuriy V.; Espinosa-Duran, John M.; Ortoleva, Peter J., E-mail: ortoleva@indiana.edu [Center for Cell and Virus Theory, Department of Chemistry, Indiana University, 800 E. Kirkwood Ave, Bloomington, Indiana 47405 (United States)

    2014-02-21

    Energy transfer between a macromolecule or supramolecular assembly and a host medium is considered from the perspective of Newton's equations and Lie-Trotter factorization. The development starts by demonstrating that the energy of the molecule evolves slowly relative to the time scale of atomic collisions-vibrations. The energy is envisioned to be a coarse-grained variable that coevolves with the rapidly fluctuating atomistic degrees of freedom. Lie-Trotter factorization is shown to be a natural framework for expressing this coevolution. A mathematical formalism and workflow for efficient multiscale simulation of energy transfer is presented. Lactoferrin and human papilloma virus capsid-like structure are used for validation.

  2. Rapid Transfer Alignment of MEMS SINS Based on Adaptive Incremental Kalman Filter.

    Science.gov (United States)

    Chu, Hairong; Sun, Tingting; Zhang, Baiqiang; Zhang, Hongwei; Chen, Yang

    2017-01-14

    In airborne MEMS SINS transfer alignment, the error of MEMS IMU is highly environment-dependent and the parameters of the system model are also uncertain, which may lead to large error and bad convergence of the Kalman filter. In order to solve this problem, an improved adaptive incremental Kalman filter (AIKF) algorithm is proposed. First, the model of SINS transfer alignment is defined based on the "Velocity and Attitude" matching method. Then the detailed algorithm progress of AIKF and its recurrence formulas are presented. The performance and calculation amount of AKF and AIKF are also compared. Finally, a simulation test is designed to verify the accuracy and the rapidity of the AIKF algorithm by comparing it with KF and AKF. The results show that the AIKF algorithm has better estimation accuracy and shorter convergence time, especially for the bias of the gyroscope and the accelerometer, which can meet the accuracy and rapidity requirement of transfer alignment.

  3. Significance of a Recurring Function in Energy Transfer

    Science.gov (United States)

    Mishra, Subodha

    2017-05-01

    The appearance of a unique function in the energy transfer from one system to the other in different physical situations such as electrical, mechanical, optical, and quantum mechanical processes is established in this work. Though the laws governing the energy transformation and its transfer from system to system are well known, here we notice a unity in diversity; a unique function appears in various cases of energy transfer whether it is a classical or a quantum mechanical process. We consider four examples, well known in elementary physics, from the fields of electricity, mechanics, optics, and quantum mechanics. We find that this unique function is in fact the transfer function corresponding to all these physical situations, and the interesting and intriguing finding is that the inverse Laplace transform of this transfer function, which is the impulse-response function of the systems when multiplied by a factor of -½, is the solution of a linear differential equation for an "instantly forced critically damped harmonic oscillator." It is important to note that though the physical phenomena considered are quite distinct, the underlying process in the language of impulse-response of the system in the time domain is a unique one. To the best of our knowledge we have not seen anywhere the above analysis of determining the unique function or its description as a transfer function in literature.

  4. A new energy transfer model for turbulent free shear flow

    Science.gov (United States)

    Liou, William W.-W.

    1992-01-01

    A new model for the energy transfer mechanism in the large-scale turbulent kinetic energy equation is proposed. An estimate of the characteristic length scale of the energy containing large structures is obtained from the wavelength associated with the structures predicted by a weakly nonlinear analysis for turbulent free shear flows. With the inclusion of the proposed energy transfer model, the weakly nonlinear wave models for the turbulent large-scale structures are self-contained and are likely to be independent flow geometries. The model is tested against a plane mixing layer. Reasonably good agreement is achieved. Finally, it is shown by using the Liapunov function method, the balance between the production and the drainage of the kinetic energy of the turbulent large-scale structures is asymptotically stable as their amplitude saturates. The saturation of the wave amplitude provides an alternative indicator for flow self-similarity.

  5. 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.

  6. Excitation energy transfer in a classical analogue of photosynthetic antennae.

    Science.gov (United States)

    Mančal, Tomáš

    2013-09-26

    We formulate a classical pure dephasing system-bath interaction model in a full correspondence to the well-studied quantum model of natural light-harvesting antennae. The equations of motion of our classical model not only represent the correct classical analogy to the quantum description of excitonic systems, but they also have exactly the same functional form. We demonstrate derivation of classical dissipation and relaxation tensor in second order perturbation theory. We find that the only difference between the classical and quantum descriptions is in the interpretation of the state and in certain limitations imposed on the parameters of the model by classical physics. The effects of delocalization, transfer pathway interference, and the transition from coherent to diffusive transfer can be found already in the classical realm. The only qualitatively new effect occurring in quantum systems is the preference for a downhill energy transfer and the resulting possibility of trapping the energy in the lowest energy state.

  7. An estimate of spherical impactor energy transfer for mechanical frequency up-conversion energy harvester

    Directory of Open Access Journals (Sweden)

    L. R. Corr

    2016-08-01

    Full Text Available Vibration energy harvesters, which use the impact mechanical frequency up-conversion technique, utilize an impactor, which gains kinetic energy from low frequency ambient environmental vibrations, to excite high frequency systems that efficiently convert mechanical energy to electrical energy. To take full advantage of the impact mechanical frequency up-conversion technique, it is prudent to understand the energy transfer from the low frequency excitations, to the impactor, and finally to the high frequency systems. In this work, the energy transfer from a spherical impactor to a multi degree of freedom spring / mass system, due to Hertzian impact, is investigated to gain insight on how best to design impact mechanical frequency up-conversion energy harvesters. Through this academic work, it is shown that the properties of the contact (or impact area, i.e., radius of curvature and material properties, only play a minor role in energy transfer and that the equivalent mass of the target system (i.e., the spring / mass system dictates the total amount of energy transferred during the impact. The novel approach of utilizing the well-known Hertzian impact methodology to gain an understanding of impact mechanical frequency up-conversion energy harvesters has made it clear that the impactor and the high frequency energy generating systems must be designed together as one system to ensure maximum energy transfer, leading to efficient ambient vibration energy harvesters.

  8. A rapid mitochondrial toxicity assay utilizing rapidly changing cell energy metabolism.

    Science.gov (United States)

    Sanuki, Yosuke; Araki, Tetsuro; Nakazono, Osamu; Tsurui, Kazuyuki

    2017-01-01

    Drug-induced liver injury is a major cause of safety-related drug-marketing withdrawals. Several drugs have been reported to disrupt mitochondrial function, resulting in hepatotoxicity. The development of a simple and effective in vitro assay to identify the potential for mitochondrial toxicity is thus desired to minimize the risk of causing hepatotoxicity and subsequent drug withdrawal. An in vitro test method called the "glucose-galactose" assay is often used in drug development but requires prior-culture of cells over several passages for mitochondrial adaptation, thereby restricting use of the assay. Here, we report a rapid version of this method with the same predictability as the original method. We found that replacing the glucose in the medium with galactose resulted in HepG2 cells immediately shifting their energy metabolism from glycolysis to oxidative phosphorylation due to drastic energy starvation; in addition, the intracellular concentration of ATP was reduced by mitotoxicants when glucose in the medium was replaced with galactose. Using our proposed rapid method, mitochondrial dysfunction in HepG2 cells can be evaluated by drug exposure for one hour without a pre-culture step. This rapid assay for mitochondrial toxicity may be more suitable for high-throughput screening than the original method at an early stage of drug development.

  9. Sustainable energy for the future. Modelling transitions to renewable and clean energy in rapidly developing countries.

    NARCIS (Netherlands)

    Urban, Frauke

    2009-01-01

    The main objective of this thesis is first to adapt energy models for the use in developing countries and second to model sustainable energy transitions and their effects in rapidly developing countries like China and India. The focus of this thesis is three-fold: a) to elaborate the differences

  10. Realistic Quantum Control of Energy Transfer in Photosynthetic Processes

    Directory of Open Access Journals (Sweden)

    Reda M. El-Shishtawy

    2016-12-01

    Full Text Available The occurrence of coherence phenomenon as a result of the interference of the probability amplitude terms is among the principle features of quantum mechanics concepts. Current experiments display the presence of quantum techniques whose coherence is supplied over large interval times. Specifically, photosynthetic mechanisms in light-harvesting complexes furnish oscillatory behaviors owing to quantum coherence. In this manuscript, we study the coherent quantum energy transfer for a single-excitation and nonlocal correlation in a dimer system (donor+acceptor displayed by two-level systems (TLSs, interacting with a cavity field with a time-dependent coupling effect considering the realistic situation of coupling between each TLS and the cavity field. We analyze and explore the specific conditions which are viable with real experimental realization for the ultimate transfer of quantum energy and nonlocal quantum correlation. We show that the enhancement of the probability for a single-excitation energy transfer greatly benefits from the energy detuning, photon-number transition, classicality of the field, and the time-dependent coupling effect. We also find that the entanglement between the donor and acceptor is very sensitive to the physical parameters and it can be generated during the coherent energy transfer.

  11. Optimal Energy Transfer in Light-Harvesting Systems

    Directory of Open Access Journals (Sweden)

    Lipeng Chen

    2015-08-01

    Full Text Available Photosynthesis is one of the most essential biological processes in which specialized pigment-protein complexes absorb solar photons, and with a remarkably high efficiency, guide the photo-induced excitation energy toward the reaction center to subsequently trigger its conversion to chemical energy. In this work, we review the principles of optimal energy transfer in various natural and artificial light harvesting systems. We begin by presenting the guiding principles for optimizing the energy transfer efficiency in systems connected to dissipative environments, with particular attention paid to the potential role of quantum coherence in light harvesting systems. We will comment briefly on photo-protective mechanisms in natural systems that ensure optimal functionality under varying ambient conditions. For completeness, we will also present an overview of the charge separation and electron transfer pathways in reaction centers. Finally, recent theoretical and experimental progress on excitation energy transfer, charge separation, and charge transport in artificial light harvesting systems is delineated, with organic solar cells taken as prime examples.

  12. Rotational Energy Transfer of N2 Gas Determined Using a New Ab Initio Potential Energy Surface

    Science.gov (United States)

    Huo, Winifred M.; Stallcop, James R.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    Rotational energy transfer between two N2 molecules is a fundamental process of some importance. Exchange is expected to play a role, but its importance is somewhat uncertain. Rotational energy transfer cross sections of N2 also have applications in many other fields including modeling of aerodynamic flows, laser operations, and linewidth analysis in nonintrusive laser diagnostics. A number of N2-N2 rigid rotor potential energy surface (PES) has been reported in the literature.

  13. Spectral energy transfer of atmospheric gravity waves through sum and difference nonlinear interactions

    Directory of Open Access Journals (Sweden)

    K. M. Huang

    2012-02-01

    Full Text Available Nonlinear interactions of gravity waves are studied with a two-dimensional, fully nonlinear model. The energy exchanges among resonant and near-resonant triads are examined in order to understand the spectral energy transfer through interactions. The results show that in both resonant and near-resonant interactions, the energy exchange between two high frequency waves is strong, but the energy transfer from large to small vertical scale waves is rather weak. This suggests that the energy cascade toward large vertical wavenumbers through nonlinear interaction is inefficient, which is different from the rapid turbulence cascade. Because of considerable energy exchange, nonlinear interactions can effectively spread high frequency spectrum, and play a significant role in limiting wave amplitude growth and transferring energy into higher altitudes. In resonant interaction, the interacting waves obey the resonant matching conditions, and resonant excitation is reversible, while near-resonant excitation is not so. Although near-resonant interaction shows the complexity of match relation, numerical experiments show an interesting result that when sum and difference near-resonant interactions occur between high and low frequency waves, the wave vectors tend to approximately match in horizontal direction, and the frequency of the excited waves is also close to the matching value.

  14. A Design Study Of A Wireless Power Transfer System For Use To Transfer Energy From A Vibration Energy Harvester

    Science.gov (United States)

    Grabham, N. J.; Harden, C.; Vincent, D.; Beeby, S. P.

    2016-11-01

    A wirelessly powered remote sensor node is presented along with its design process. The purpose of the node is the further expansion of the sensing capabilities of the commercial Perpetuum system used for condition monitoring on trains and rolling stock which operates using vibration energy harvesting. Surplus harvested vibration energy is transferred wirelessly to a remote satellite sensor to allow measurements over a wider area to be made. This additional data is to be used for long term condition monitoring. Performance measurements made on the prototype remote sensor node are reported and advantages and disadvantages of using the same RF frequency for power and data transfer are identified.

  15. Phonon-mediated path-interference in electronic energy transfer.

    Science.gov (United States)

    Hossein-Nejad, Hoda; Olaya-Castro, Alexandra; Scholes, Gregory D

    2012-01-14

    We present a formalism to quantify the contribution of path-interference in phonon-mediated electronic energy transfer. The transfer rate between two molecules is computed by considering the quantum mechanical amplitudes associated with pathways connecting the initial and final sites. This includes contributions from classical pathways, but also terms arising from interference of different pathways. We treat the vibrational modes coupled to the molecules as a non-Markovian harmonic oscillator bath, and investigate the correction to transfer rates due to the lowest-order interference contribution. We show that depending on the structure of the harmonic bath, the correction due to path-interference may have a dominant vibrational or electronic character, and can make a notable contribution to the transfer rate in the steady state.

  16. SY-101 Rapid Transfer Project Low Temperature Operations Review and Recommendations to Support Lower Temperature Limits

    Energy Technology Data Exchange (ETDEWEB)

    HICKMAN, G.L.

    2000-01-10

    The lower temperature limit for the 241 SY-101 RAPID transfer project is currently set at 20 F Based on the analysis and recommendations in this document this limit can be lowered to 0 F. Analysis of all structures systems and components (SSCs) indicate that a reduction in operating temperature may be achieved with minor modifications to field-installed equipment. Following implementation of these changes it is recommended that the system requirements be amended to specify a temperature range for transfer or back dilute evolutions of 0 F to 100 F.

  17. 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 ...

  18. Energy transfer and thermal studies of Pr doped cerium oxalate ...

    Indian Academy of Sciences (India)

    Administrator

    School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, India. MS received 7 December 2009; revised 12 August 2010. Abstract. Energy transfer process at room temperature for cerium (sensitizer) oxalate single crystals doped with different concentrations (10, 13, 15, 17 and 20%) of praseodymium ions ...

  19. Metaphors Describing Energy Transfer through Ecosystems: Helpful or Misleading?

    Science.gov (United States)

    Wernecke, Ulrike; Schwanewedel, Julia; Harms, Ute

    2018-01-01

    Energy transfer in ecosystems is an abstract and challenging topic for learners. Metaphors are widely used in scientific and educational discourse to communicate ideas about abstract phenomena. However, although considered valuable teaching tools, metaphors are ambiguous and can be misleading when used in educational contexts. Educational…

  20. 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

  1. Energy transfer in photosynthesis: experimental insights and quantitative models

    NARCIS (Netherlands)

    van Grondelle, R.; Novoderezhkin, V.

    2006-01-01

    We overview experimental and theoretical studies of energy transfer in the photosynthetic light-harvesting complexes LH1, LH2, and LHCII performed during the past decade since the discovery of high-resolution structure of these complexes. Experimental findings obtained with various spectroscopic

  2. 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.

  3. 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 ...

  4. Excitation energy transfer processes in condensed matter theory and applications

    CERN Document Server

    Singh, Jai

    1994-01-01

    Applying a unified quantum approach, contributors offer fresh insights into the theoretical developments in the excitation energy transfer processes in condensed matter This comprehensive volume examines Frenkel and Wannier excitonic processes; rates of excitonic processes; theory of laser sputter and polymer ablation; and polarons, excitonic polarons and self-trapping

  5. Excitation energy transfer from dye molecules to doped graphene

    Indian Academy of Sciences (India)

    Excitation energy transfer from dye molecules to doped graphene. #. R S SWATHIa and K L SEBASTIANb,∗. aSchool of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram 695 016, India. bDepartment of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, ...

  6. Excitation energy transfer from dye molecules to doped graphene

    Indian Academy of Sciences (India)

    Recently, we have reported theoretical studies on the rate of energy transfer from an electronically excited molecule to graphene. It was found that graphene is a very efficient quencher of the electronically excited states and that the rate -4. The process was found to be effective up to 30 which is well beyond the ...

  7. 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 ...

  8. Wireless energy transfer: Dielectric lens antennas for beam shaping in wireless power-transfer applications

    Science.gov (United States)

    Gonçalves, Ricardo; Carvalho, Nuno B.; Pinho, Pedro

    2017-02-01

    In the current contest of wireless systems, the last frontier remains the cut of the power cord. In that sense, the interest over wireless energy transfer technologies in the past years has grown exponentially. However, there are still many challenges to be overcome in order to enable wireless energy transfer full potential. One of the focus in the development of such systems is the design of very-high-gain, highly efficient, antennas that can compensate for the propagation loss of radio signals over the air. In this paper, we explore the design and manufacturing process of dielectric lenses, fabricated using a professional-grade desktop 3D printer. Lens antennas are used in order to increase beam efficiency and therefore maximize the efficiency of a wireless power-transfer system operating at microwave frequencies in the Ku band. Measurements of two fabricated prototypes showcase a large directivity, as predicted with simulations. xml:lang="fr"

  9. Modeling crossed-beam energy transfer for inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Marion, D. J. Y. [CEA, DAM, DIF, F-91297 Arpajon Cedex (France); Univ. Bordeaux, CEA, CNRS, CELIA, UMR5107, F-33400 Talence (France); Debayle, A., E-mail: arnaud.debayle@cea.fr; Masson-Laborde, P.-E.; Loiseau, P.; Casanova, M. [CEA, DAM, DIF, F-91297 Arpajon Cedex (France)

    2016-05-15

    We developed a numerical code that describes both the energy transfer occurring when two or more laser beams overlap in a weakly non-homogeneous plasma, and the beam energy losses associated with the electron-ion collisions. The numerical solutions are validated with both the exact analytical solutions in homogeneous plasmas, and with new approximate analytical solutions in non-homogeneous plasmas that include the aforementioned inverse bremsstrahlung effect. Comparisons with kinetic particle-in-cell simulations are satisfactory, provided the acoustic wave-breaking limit and the self-focusing regime are not reached. An application of the Cross-Beam Energy Transfer model is shown for a typical case of indirect-drive implosion in a gold hohlraum.

  10. Validation of Contamination Control in Rapid Transfer Port Chambers for Pharmaceutical Manufacturing Processes

    OpenAIRE

    Shih-Cheng Hu; Angus Shiue; Han-Yang Liu; Rong-Ben Chiu

    2016-01-01

    There is worldwide concern with regard to the adverse effects of drug usage. However, contaminants can gain entry into a drug manufacturing process stream from several sources such as personnel, poor facility design, incoming ventilation air, machinery and other equipment for production, etc. In this validation study, we aimed to determine the impact and evaluate the contamination control in the preparation areas of the rapid transfer port (RTP) chamber during the pharmaceutical manufacturing...

  11. State-of-the-Art Developments of Acoustic Energy Transfer

    Directory of Open Access Journals (Sweden)

    Md Rabiul Awal

    2016-01-01

    Full Text Available Acoustic energy transfer (AET technology has drawn significant industrial attention recently. This paper presents the reviews of the existing AETs sequentially, preferably, from the early stage. From the review, it is evident that, among all the classes of wireless energy transfer, AET is the safest technology to adopt. Thus, it is highly recommended for sensitive area and devices, especially implantable devices. Though, the efficiency for relatively long distances (i.e., >30 mm is less than that of inductive or capacitive power transfer; however, the trade-off between safety considerations and performances is highly suitable and better than others. From the presented statistics, it is evident that AET is capable of transmitting 1.068 kW and 5.4 W of energy through wall and in-body medium (implants, respectively. Progressively, the AET efficiency can reach up to 88% in extension to 8.6 m separation distance which is even superior to that of inductive and capacitive power transfer.

  12. Rates of mass, momentum, and energy transfer at the magnetopause

    Science.gov (United States)

    Hill, T. W.

    1979-01-01

    Empirical estimates of the global rates of transfer of solar wind mass, tangential momentum, and energy at the Earth's magnetopause are presented for comparison against model estimates based on the four principal mechanisms that have been proposed to explain such transfer. The comparisons, although not quite conclusive, strongly favor a model that incorporates some combination of direct magnetic connection and anomalous cross field diffusion. An additional global constraint, the rate at which magnetic flux is cycled through the magnetospheric convection system, strongly suggests that direct magnetic connection plays a significant if not dominant role in the solar wind/magnetosphere interaction.

  13. Study of elementary transfer mechanisms during a collision between a swift multi-charged heavy ion and a neutral atom; Etude des mecanismes elementaires de transfert d`energie au cours d`une collision entre un ion lourd rapide multi-charge et un atome neutre

    Energy Technology Data Exchange (ETDEWEB)

    Jardin, P. [Caen Univ., 14 (France)

    1995-12-31

    This work is dedicated to the study of the energy transfer mechanisms which occur during a collision between a swift multicharged heavy ion and a neutral atom. The elementary energy energy transfer mechanisms (scattering, excitation, ionization, capture) and their consequences on the target velocity after the collision (recoil velocity) are recalled in the first chapter. In the case of small projectile diffusion angles, we show that the recoil velocity component, transverse to the incident projectile direction, results principally from the diffusion mechanism, while the longitudinal component is due essentially to the mass transfer and the inelastic energy transfer mechanisms. Since the target recoil velocities are very small, we have built an experimental set-up which reduces the impreciseness on their measurement due to the target thermal spread using, as targets, cooled atoms of a supersonic jet (temperature < 1 K). The association of time of flight and localisation techniques allows us, for each ionised target atom, to determine the three recoil velocity components with a very good accuracy (a few tens of meters per second). In chapter three, we describe the data analysis method. And then we present in the last chapter the results we have obtained for the collision systems Xe{sup 44+}(6.7 MeV/A) + Ar => Xe{sup 44} + Ar{sup q+}+qe{sup -} (q ranging from 1 to 7); Xe{sup 44+} (6.7 MeV/A) + He => Xe{sup 44+} He{sup 1+,2+}+1e{sup -},2e{sup -}. We show that it is possible to interpret the recoil velocity in terms of kinetic energy transferred to the target and to the electrons ejected from the target. (author) 44 refs.

  14. Clinical scale rapid expansion of lymphocytes for adoptive cell transfer therapy in the WAVE® bioreactor

    Science.gov (United States)

    2012-01-01

    Background To simplify clinical scale lymphocyte expansions, we investigated the use of the WAVE®, a closed system bioreactor that utilizes active perfusion to generate high cell numbers in minimal volumes. Methods We have developed an optimized rapid expansion protocol for the WAVE bioreactor that produces clinically relevant numbers of cells for our adoptive cell transfer clinical protocols. Results TIL and genetically modified PBL were rapidly expanded to clinically relevant scales in both static bags and the WAVE bioreactor. Both bioreactors produced comparable numbers of cells; however the cultures generated in the WAVE bioreactor had a higher percentage of CD4+ cells and had a less activated phenotype. Conclusions The WAVE bioreactor simplifies the process of rapidly expanding tumor reactive lymphocytes under GMP conditions, and provides an alternate approach to cell generation for ACT protocols. PMID:22475724

  15. 2013 MOLECULAR ENERGY TRANSFER GORDON RESEARCH CONFERENCE (JANUARY 13-18, 2013 - VENTURA BEACH MARRIOTT, VENTURA CA

    Energy Technology Data Exchange (ETDEWEB)

    Reid, Scott A. [Marquette University

    2012-10-18

    Sessions covered all areas of molecular energy transfer, with 10 sessions of talks and poster sessions covering the areas of :  Energy Transfer in Inelastic and Reactive Scattering  Energy Transfer in Photoinitiated and Unimolecular Reactions  Non-adiabatic Effects in Energy TransferEnergy Transfer at Surfaces and Interfaces  Energy Transfer in Clusters, Droplets, and Aerosols  Energy Transfer in Solution and Solid  Energy Transfer in Complex Systems  Energy Transfer: New vistas and horizons  Molecular Energy Transfer: Where Have We Been and Where are We Going?

  16. Reduced density matrix hybrid approach: Application to electronic energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Berkelbach, Timothy C.; Reichman, David R. [Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027 (United States); Markland, Thomas E. [Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305 (United States)

    2012-02-28

    Electronic energy transfer in the condensed phase, such as that occurring in photosynthetic complexes, frequently occurs in regimes where the energy scales of the system and environment are similar. This situation provides a challenge to theoretical investigation since most approaches are accurate only when a certain energetic parameter is small compared to others in the problem. Here we show that in these difficult regimes, the Ehrenfest approach provides a good starting point for a dynamical description of the energy transfer process due to its ability to accurately treat coupling to slow environmental modes. To further improve on the accuracy of the Ehrenfest approach, we use our reduced density matrix hybrid framework to treat the faster environmental modes quantum mechanically, at the level of a perturbative master equation. This combined approach is shown to provide an efficient and quantitative description of electronic energy transfer in a model dimer and the Fenna-Matthews-Olson complex and is used to investigate the effect of environmental preparation on the resulting dynamics.

  17. Rapid Response Team Calls and Unplanned Transfers to the Pediatric Intensive Care Unit in a Pediatric Hospital.

    Science.gov (United States)

    Humphreys, Stacey; Totapally, Balagangadhar R

    2016-01-01

    Variability in disposition of children according to the time of rapid response calls is unknown. To evaluate times and disposition of rapid response alerts and outcomes for children transferred from acute care to intensive care. Deidentified data on demographics, time and disposition of the child after activation of a rapid response, time of transfer to intensive care, and patient outcomes were reviewed retrospectively. Data for rapid-response patients on time of activation of the response and unplanned transfers to the intensive care unit were compared with data on other patients admitted to the unit. Of 542 rapid responses activated, 321 (59.2%) were called during the daytime. Out of all rapid response activations, 323 children (59.6%) were transferred to intensive care, 164 (30.3%) remained on the general unit, and 19 (3.5%) required resuscitation. More children were transferred to intensive care after rapid response alerts (P = .048) during the daytime (66%) than at night (59%). During the same period, 1313 patients were transferred to intensive care from acute care units. Age, sex, risk of mortality, length of stay, and mortality rate did not differ according to the time of transfer. Mortality among unplanned transfers (3.8%) was significantly higher (P intensive care patients (1.4%). Only 25% of transfers from acute care units to the intensive care unit occurred after activation of a rapid response team. Most rapid responses were called during daytime hours. Mortality was significantly higher among unplanned transfers from acute care than among other intensive care admissions. ©2016 American Association of Critical-Care Nurses.

  18. Model Property Based Material Balance and Energy Conservation Analysis for Process Industry Energy Transfer Systems

    OpenAIRE

    Fumin Ma; Gregory M. P. O’Hare; Tengfei Zhang; Michael J. O’Grady

    2015-01-01

    Conventional historical data based material and energy balance analyses are static and isolated computations. Such methods cannot embody the cross-coupling effect of energy flow, material flow and information flow in the process industry; furthermore, they cannot easily realize the effective evaluation and comparison of different energy transfer processes by alternating the model module. In this paper, a novel method for material balance and energy conservation analysis of process industry en...

  19. A wireless energy transfer platform, integrated at the bedside.

    Science.gov (United States)

    De Clercq, Hans; Puers, Robert

    2013-01-01

    This paper presents the design of a wireless energy transfer platform, integrated at the bedside. The system contains a matrix of identical inductive power transmitters, which are optimised to provide power to a wearable sensor network, with the purpose of wirelessly recording vital signals over an extended period of time. The magnetic link, operates at a transfer frequency of 6.78MHz and is able to transfer a power of 3.3mW to the remote side at an inter-coil distance of 100mm. The total efficiency of the power link is 26%. Moreover, the platform is able to dynamically determine the position of freely moving sensor nodes and selectively induce a magnetic field in the area where the sensor nodes are positioned. As a result, the patient will not be subjected to unnecessary radiation and the specific absorption rate standards are met more easily.

  20. Regulation control and energy management scheme for wireless power transfer

    Science.gov (United States)

    Miller, John M.

    2015-12-29

    Power transfer rate at a charging facility can be maximized by employing a feedback scheme. The state of charge (SOC) and temperature of the regenerative energy storage system (RESS) pack of a vehicle is monitored to determine the load due to the RESS pack. An optimal frequency that cancels the imaginary component of the input impedance for the output signal from a grid converter is calculated from the load of the RESS pack, and a frequency offset f* is made to the nominal frequency f.sub.0 of the grid converter output based on the resonance frequency of a magnetically coupled circuit. The optimal frequency can maximize the efficiency of the power transfer. Further, an optimal grid converter duty ratio d* can be derived from the charge rate of the RESS pack. The grid converter duty ratio d* regulates wireless power transfer (WPT) power level.

  1. Interglobular Diffusion of an Energy Donor in Triplet-Triplet Energy Transfer in Proteins

    Directory of Open Access Journals (Sweden)

    Andrey G. Melnikov

    2013-01-01

    Full Text Available The triplet-triplet energy transfer between polar molecules of luminescent probe (eosin as an energy donor and nonpolar molecules of energy acceptor (anthracene is studied. Both the donor and the acceptor are bound to human serum albumin by noncovalent bonds. A dependence of rate constant of triplet-triplet energy transfer on human serum albumin concentration is revealed. A rate constant of eosin output from protein globules is determined. It is shown that the energy transfer occurs as a result of interglobular diffusion of eosin. The obtained results indicate that a protein-luminescent probe based sensor can be used for testing a concentration of polycyclic aromatic hydrocarbons in proteins.

  2. An assessment of various blood collection and transfer methods used for malaria rapid diagnostic tests

    Directory of Open Access Journals (Sweden)

    Baik Fred

    2007-11-01

    Full Text Available Abstract Background Four blood collection and transfer devices commonly used for malaria rapid diagnostic tests (RDTs were assessed for their consistency, accuracy and ease of use in the hands of laboratory technicians and village health workers. Methods Laboratory technicians and village health workers collected blood from a finger prick using each device in random order, and deposited the blood either on filter paper or into a suitable casette-type RDT. Consistency and accuracy of volume delivered was determined by comparing the measurements of the resulting blood spots/heights with the measurements of laboratory-prepared pipetted standard volumes. The effect of varying blood volumes on RDT sensitivity and ease of use was also observed. Results There was high variability in blood volume collected by the devices, with the straw and the loop, the most preferred devices, usually transferring volumes greater than intended, while the glass capillary tube and the plastic pipette transferring less volume than intended or none at all. Varying the blood volume delivered to RDTs indicated that this variation is critical to RDT sensitivity only when the transferred volume is very low. Conclusion None of the blood transfer devices assessed performed consistently well. Adequate training on their use is clearly necessary, with more development efforts for improved designs to be used by remote health workers, in mind.

  3. Space-to-Space Power Beaming Enabling High Performance Rapid Geocentric Orbit Transfer

    Science.gov (United States)

    Dankanich, John W.; Vassallo, Corinne; Tadge, Megan

    2015-01-01

    The use of electric propulsion is more prevalent than ever, with industry pursuing all electric orbit transfers. Electric propulsion provides high mass utilization through efficient propellant transfer. However, the transfer times become detrimental as the delta V transitions from near-impulsive to low-thrust. Increasing power and therefore thrust has diminishing returns as the increasing mass of the power system limits the potential acceleration of the spacecraft. By using space-to-space power beaming, the power system can be decoupled from the spacecraft and allow significantly higher spacecraft alpha (W/kg) and therefore enable significantly higher accelerations while maintaining high performance. This project assesses the efficacy of space-to-space power beaming to enable rapid orbit transfer while maintaining high mass utilization. Concept assessment requires integrated techniques for low-thrust orbit transfer steering laws, efficient large-scale rectenna systems, and satellite constellation configuration optimization. This project includes the development of an integrated tool with implementation of IPOPT, Q-Law, and power-beaming models. The results highlight the viability of the concept, limits and paths to infusion, and comparison to state-of-the-art capabilities. The results indicate the viability of power beaming for what may be the only approach for achieving the desired transit times with high specific impulse.

  4. Incorporating the Delphi Technique to investigate renewable energy technology transfer in Saudi Arabia

    Science.gov (United States)

    Al-Otaibi, Nasir K.

    Saudi Arabia is a major oil-producing nation facing a rapidly-growing population, high unemployment, climate change, and the depletion of its natural resources, potentially including its oil supply. Technology transfer is regarded as a means to diversify countries' economies beyond their natural resources. This dissertation examined the opportunities and barriers to utilizing technology transfer successfully to build renewable energy resources in Saudi Arabia to diversify the economy beyond oil production. Examples of other developing countries that have successfully used technology transfer to transform their economies are explored, including Japan, Malayasia, and the United Arab Emirates. Brazil is presented as a detailed case study to illustrate its transition to an economy based to a much greater degree than before on renewable energy. Following a pilot study, the Delphi Method was used in this research to gather the opinions of a panel of technology transfer experts consisting of 10 heterogeneous members of different institutions in the Kingdom of Saudi Arabia, including aviation, telecommunication, oil industry, education, health systems, and military and governmental organizations. In three rounds of questioning, the experts identified Education, Dependence on Oil, and Manpower as the 3 most significant factors influencing the potential for success of renewable energy technology transfer for Saudi Arabia. Political factors were also rated toward the "Very Important" end of a Likert scale and were discussed as they impact Education, Oil Dependence, and Manpower. The experts' opinions are presented and interpreted. They form the basis for recommended future research and discussion of how in light of its political system and its dependence on oil, Saudi Arabia can realistically move forward on renewable energy technology transfer and secure its economic future.

  5. Quantum dot-dye hybrid systems for energy transfer applications

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Ting

    2010-07-01

    In this thesis, we focus on the preparation of energy transfer-based quantum dot (QD)-dye hybrid systems. Two kinds of QD-dye hybrid systems have been successfully synthesized: QD-silica-dye and QD-dye hybrid systems. In the QD-silica-dye hybrid system, multishell CdSe/CdS/ZnS QDs were adsorbed onto monodisperse Stoeber silica particles with an outer silica shell of thickness 2-24 nm containing organic dye molecules (Texas Red). The thickness of this dye layer has a strong effect on the total sensitized acceptor emission, which is explained by the increase in the number of dye molecules homogeneously distributed within the silica shell, in combination with an enhanced surface adsorption of QDs with increasing dye amount. Our conclusions were underlined by comparison of the experimental results with Monte-Carlo simulations, and by control experiments confirming attractive interactions between QDs and Texas Red freely dissolved in solution. New QD-dye hybrid system consisting of multishell QDs and organic perylene dyes have been synthesized. We developed a versatile approach to assemble extraordinarily stable QD-dye hybrids, which uses dicarboxylate anchors to bind rylene dyes to QD. This system yields a good basis to study the energy transfer between QD and dye because of its simple and compact design: there is no third kind of molecule linking QD and dye; no spacer; and the affinity of the functional group to the QD surface is strong. The FRET signal was measured for these complexes as a function of both dye to QD ratio and center-to-center distance between QD and dye by controlling number of covered ZnS layers. Data showed that fluorescence resonance energy transfer (FRET) was the dominant mechanism of the energy transfer in our QD-dye hybrid system. FRET efficiency can be controlled by not only adjusting the number of dyes on the QD surface or the QD to dye distance, but also properly choosing different dye and QD components. Due to the strong stability, our QD

  6. Modelling excitonic-energy transfer in light-harvesting complexes

    CERN Document Server

    Kramer, Tobias

    2014-01-01

    The theoretical and experimental study of energy transfer in photosynthesis has revealed an interesting transport regime, which lies at the borderline between classical transport dynamics and quantum-mechanical interference effects. Dissipation is caused by the coupling of electronic degrees of freedom to vibrational modes and leads to a directional energy transfer from the antenna complex to the target reaction-center. The dissipative driving is robust and does not rely on fine-tuning of specific vibrational modes. For the parameter regime encountered in the biological systems new theoretical tools are required to directly compare theoretical results with experimental spectroscopy data. The calculations require to utilize massively parallel graphics processor units (GPUs) for efficient and exact computations.

  7. Electromagnetic Energy Absorption due to Wireless Energy Transfer: A Brief Review

    Directory of Open Access Journals (Sweden)

    Syafiq A.

    2016-01-01

    Full Text Available This paper reviews an implementation of evaluating compliance of wireless power transfer systems with respect to human electromagnetic exposure limits. Methods for both numerical analysis and measurements are discussed. The objective is to evaluate the rate of which energy is absorbed by the human body when exposed to a wireless energy transfer, although it can be referred to the absorption of other forms of energy by tissue. An exposure assessment of a representative wireless power transfer system, under a limited set of operating conditions, is provided in order to estimate the maximum SAR levels. The aim of this review is to conclude the possible side effect to the human body when utilizing wireless charging in daily life so that an early severe action can be taken when using wireless transfer.

  8. 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

  9. Beyond superquenching: Hyper-efficient energy transfer from conjugated polymers to gold nanoparticles

    Science.gov (United States)

    Fan, Chunhai; Wang, Shu; Hong, Janice W.; Bazan, Guillermo C.; Plaxco, Kevin W.; Heeger, Alan J.

    2003-01-01

    Gold nanoparticles quench the fluorescence of cationic polyfluorene with Stern–Volmer constants (KSV) approaching 1011 M—1, several orders of magnitude larger than any previously reported conjugated polymer–quencher pair and 9–10 orders of magnitude larger than small molecule dye–quencher pairs. The dependence of KSV on ionic strength, charge and conjugation length of the polymer, and the dimensions (and thus optical properties) of the nanoparticles suggests that three factors account for this extraordinary efficiency: (i) amplification of the quenching via rapid internal energy or electron transfer, (ii) electrostatic interactions between the cationic polymer and anionic nanoparticles, and (iii) the ability of gold nanoparticles to quench via efficient energy transfer. As a result of this extraordinarily high KSV, quenching can be observed even at subpicomolar concentrations of nanoparticles, suggesting that the combination of conjugated polymers with these nanomaterials can potentially lead to improved sensitivity in optical biosensors. PMID:12750470

  10. Nanoscale heat transfer and thermoelectrics for alternative energy

    Science.gov (United States)

    Robinson, Richard

    2011-03-01

    In the area of alternative energy, thermoelectrics have experienced an unprecedented growth in popularity because of their ability to convert waste heat into electricity. Wired in reverse, thermoelectrics can act as refrigeration devices, where they are promising because they are small in size and lightweight, have no moving parts, and have rapid on/off cycles. However, due to their low efficiencies bulk thermoelectrics have historically been a niche market. Only in the last decade has thermoelectric efficiency exceeded ~ 20 % due to fabrication of nanostructured materials. Nanoscale materials have this advantage because electronic and acoustic confinement effects can greatly increase thermoelectric efficiency beyond bulk values. In this talk, I will introduce our work in the area of nanoscale heat transfer with the goal of more efficient thermoelectrics. I will discuss our experiments and methods to study acoustic confinement in nanostructures and present some of our new nanostructured thermoelectric materials. To study acoustic confinement we are building a nanoscale phonon spectrometer. The instrument can excite phonon modes in nanostructures in the ~ 100 s of GHz. Ballistic phonons from the generator are used to probe acoustic confinement and surface scattering effects. Transmission studies using this device will help optimize materials and morphologies for more efficient nanomaterial-based thermoelectrics. For materials, our group has synthesized nano-layer superlattices of Na x Co O2 . Sodium cobaltate was recently discovered to have a high Seebeck coeficent and is being studied as an oxide thermoelectric material. The thickness of our nano-layers ranges from 5 nm to 300 nm while the lengths can be varied between 10 μ m and 4 mm. Typical aspect ratios are 40 nm: 4 mm, or 1:100,000. Thermoelectric characterization of samples with tilted multiple-grains along the measurement axis indicate a thermoelectric efficiency on par with current polycrystalline samples

  11. Model Property Based Material Balance and Energy Conservation Analysis for Process Industry Energy Transfer Systems

    Directory of Open Access Journals (Sweden)

    Fumin Ma

    2015-10-01

    Full Text Available Conventional historical data based material and energy balance analyses are static and isolated computations. Such methods cannot embody the cross-coupling effect of energy flow, material flow and information flow in the process industry; furthermore, they cannot easily realize the effective evaluation and comparison of different energy transfer processes by alternating the model module. In this paper, a novel method for material balance and energy conservation analysis of process industry energy transfer system is developed based on model property. Firstly, a reconfigurable energy transfer process model, which is independent of energy types and energy-consuming equipment, is presented from the viewpoint of the cross-coupling effect of energy flow, material flow and information flow. Thereafter the material balance determination is proposed based on both a dynamic incidence matrix and dynamic balance quantity. Moreover, the model-weighted conservation determination theorem is proved, and the energy efficiency analysis method is also discussed. Results confirmed the efficacy of the proposed methods, confirming its potential for use by process industry in energy efficiency analyses.

  12. Photoluminescence and energy transfer in PVK/DCM blends

    Science.gov (United States)

    Bruno, Annalisa; Del Mauro, Anna De Girolamo; Nenna, Giuseppe; Maglione, Maria Grazia; Minarini, Carla

    2012-07-01

    In this work, the photophysical proprieties of 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) dye in the poly-vinylcarbazole (PVK) matrix are analyzed with a particular attention to the energy transfer processes between the matrix and the dye. PVP films with varying weight percent (from 1 to 8 wt%) of DCM have been fabricated. The presence of DCM induces a red shift in the emission spectra of the blend and a quenching effect in the excitons lifetime increasing the concentration of the dopants. These two phenomena have been studied in terms of energy processes inside the blends.

  13. State-to-state dynamics of molecular energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Gentry, W.R.; Giese, C.F. [Univ. of Minnesota, Minneapolis (United States)

    1993-12-01

    The goal of this research program is to elucidate the elementary dynamical mechanisms of vibrational and rotational energy transfer between molecules, at a quantum-state resolved level of detail. Molecular beam techniques are used to isolate individual molecular collisions, and to control the kinetic energy of collision. Lasers are used both to prepare specific quantum states prior to collision by stimulated-emission pumping (SEP), and to measure the distribution of quantum states in the collision products by laser-induced fluorescence (LIF). The results are interpreted in terms of dynamical models, which may be cast in a classical, semiclassical or quantum mechanical framework, as appropriate.

  14. Excitation energy transfer in a non-markovian dynamical disordered environment: localization, narrowing, and transfer efficiency.

    Science.gov (United States)

    Chen, Xin; Silbey, Robert J

    2011-05-12

    The non-markovian effect of a fluctuating environment plays an important role in electronic excitation transfer in organic disordered media, such as light-harvesting systems and conjugated polymers. Stochastic Liouville equations (SLE) are used to study the interaction between excitons and the environment. We model the non-markovian environment phenomenologically with a dichotomic process. An exact approach to solve the SLE based on Shapiro and Loginov's differentiation formulas allows us to rigorously study the effect of the non-markovian environment on excitation energy transfer, such as coherence conservation and its implication for transfer efficiency. This simple SLE model goes beyond the perturbative second-order master equation valid for both the weak coupling and short time correlation conditions. In addition, we discuss why our non-markovian model is a good approximation to the SLE model driven by the stationary Gauss-Markov process (Ornstein-Uhlenbeck process) over a broad range of fluctuation strengths and correlation times. Numerical results based on our SLE model for dimeric aggregates and the Fenna-Matthews-Olson (FMO) complex reveal the important interplay of intermolecular coupling, correlation time, and fluctuation strength, and their effects on the exciton relaxation process due to the environmental phonon. The results also uncover the connection between localization and motional narrowing, and the efficiency of electronic excitation transfer, demonstrating that the non-markovian environment is critical for chromophore aggregates to achieve an optimal transfer rate in a noisy environment and to contribute to the robustness of the FMO excitation energy transfer network.

  15. Analysis of the Coupling Coefficient in Inductive Energy Transfer Systems

    Directory of Open Access Journals (Sweden)

    Rafael Mendes Duarte

    2014-01-01

    Full Text Available In wireless energy transfer systems, the energy is transferred from a power source to an electrical load without the need of physical connections. In this scope, inductive links have been widely studied as a way of implementing these systems. Although high efficiency can be achieved when the system is operating in a static state, it can drastically decrease if changes in the relative position and in the coupling coefficient between the coils occur. In this paper, we analyze the coupling coefficient as a function of the distance between two planar and coaxial coils in wireless energy transfer systems. A simple equation is derived from Neumann’s equation for mutual inductance, which is then used to calculate the coupling coefficient. The coupling coefficient is computed using CST Microwave Studio and compared to calculation and experimental results for two coils with an excitation signal of up to 10 MHz. The results showed that the equation presents good accuracy for geometric parameters that do not lead the solution of the elliptic integral of the first kind to infinity.

  16. 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

  17. metal-induced energy transfer (MIET) (Conference Presentation)

    Science.gov (United States)

    Karedla, Narain V. S.; Isbaner, Sebastian; Chizhik, Alexey I.; Gregor, Ingo; Enderlein, Joerg; Chizhik, Anna M.

    2017-02-01

    We present a new concept for measuring distance values of single molecules from a surface with nanometer accuracy using the energy transfer from the excited molecule to surface plasmons of a metal film [1]. We measure the fluorescence lifetime of individual dye molecules deposited on a dielectric spacer as a function of a spacer thickness. By using our theoretical model [2], we convert the lifetime values into the axial distance of individual molecules. Similar to Förster resonance energy transfer (FRET), this allows emitters to be localized with nanometer accuracy, but in contrast to FRET the distance range at which efficient energy transfer takes place is an order of magnitude larger. Together with orientation measurements [3], one can potentially use smMIET to localize single emitters with a nanometer precision isotropically, which will facilitate intra- and intermolecular distance measurements in biomolecules and complexes, circumventing the requirement of the knowledge of mutual orientations between two dipole emitters which severely limits the quantification of such distances from a conventional single-pair FRET (spFRET) experiment. [1] Karedla, N., Chizhik, A.I., Gregor, I., Chizhik, A.M., Schulz, O., Enderlein, J., ChemPhysChem, 15, 705-711 (2014). [2] Enderlein J., Biophyical Journal, 78, 2151-8 (2000). [3] Karedla, N., Stein, S. C., Hähnel, D., Gregor, I., Chizhik, A., and Enderlein, J., Physical Review Letters, 115, 173002 (2015).

  18. Energy and Information Transfer Via Coherent Exciton Wave Packets

    Science.gov (United States)

    Zang, Xiaoning

    Electronic excitons are bound electron-hole states that are generated when light interacts with matter. Such excitations typically entangle with phonons and rapidly decohere; the resulting electronic state dynamics become diffusive as a result. However, if the exciton-phonon coupling can be reduced, it may be possible to construct excitonic wave packets that offer a means of efficiently transmitting information and energy. This thesis is a combined theory/computation investigation to design condensed matter systems which support the requisite coherent transport. Under the idealizing assumption that exciton-phonon entanglement could be completely suppressed, the majority of this thesis focuses on the creation and manipulation of exciton wave packets in quasi-one-dimensional systems. While each site could be a silicon quantum dot, the actual implementation focused on organic molecular assemblies for the sake of computational simplicity, ease of experimental implementation, potential for coherent transport, and promise because of reduced structural uncertainty. A laser design was derived to create exciton wave packets with tunable shape and speed. Quantum interference was then exploited to manipulate these packets to block, pass, and even dissociate excitons based on their energies. These developments allow exciton packets to be considered within the arena of quantum information science. The concept of controllable excitonic wave packets was subsequently extended to consider molecular designs that allow photons with orbital angular momentum to be absorbed to create excitons with a quasi-angular momentum of their own. It was shown that a well-defined measure of topological charge is conserved in such light-matter interactions. Significantly, it was also discovered that such molecules allow photon angular momenta to be combined and later emitted. This amounts to a new way of up/down converting photonic angular momentum without relying on nonlinear optical materials. The

  19. Energy-donor phosphorescence quenching study of triplet–triplet energy transfer between UV absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Azusa; Nakabai, Yuya [Department of Chemistry, Graduate School of Engineering, Yokohama National University, Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan); Oguchi-Fujiyama, Nozomi; Miyazawa, Kazuyuki [Shiseido Research Center, Hayabuchi, Tsuzuki-ku, Yokohama 224-8558 (Japan); Yagi, Mikio, E-mail: yagimiki@ynu.ac.jp [Department of Chemistry, Graduate School of Engineering, Yokohama National University, Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan)

    2015-10-15

    The intermolecular triplet–triplet energy transfer from a photounstable UV-A absorber, 4-tert-butyl-4′-methoxydibenzoylmethane (BMDBM), to UV-B absorbers, 2-ethylhexyl 4-methoxycinnamate (octyl methoxycinnamate, OMC), octocrylene (OCR) and dioctyl 4-methoxybenzylidenemalonate (DOMBM) has been observed using a 355 nm laser excitation in rigid solutions at 77 K. The decay curves of the energy-donor phosphorescence in the presence of the UV-B absorbers deviate from the exponential decay at the initial stage of the decay. The Stern–Volmer formulation is not valid in rigid solutions because molecular diffusion is impossible. The experimental results indicate that the rate constant of triplet–triplet energy transfer from BMDBM to the UV-B absorbers, k{sub T–T}, decreases in the following order: k{sub T–T} (BMDBM–DOMBM)>k{sub T–T} (BMDBM–OMC)≥k{sub T–T} (BMDBM–OCR). The presence of DOMBM enhances the photostability of the widely used combination of UV-A and UV-B absorbers, BMDBM and OCR. The effects of the triplet–triplet energy transfer on the photostability of BMDBM are discussed. - Highlights: • The intermolecular triplet–triplet energy transfer between UV absorbers was observed. • The phosphorescence decay deviates from exponential at the initial stage of decay. • The effects of triplet–triplet energy transfer on the photostability are discussed.

  20. Heat transfer and flow in solar energy and bioenergy systems

    Science.gov (United States)

    Xu, Ben

    The demand for clean and environmentally benign energy resources has been a great concern in the last two decades. To alleviate the associated environmental problems, reduction of the use of fossil fuels by developing more cost-effective renewable energy technologies becomes more and more significant. Among various types of renewable energy sources, solar energy and bioenergy take a great proportion. This dissertation focuses on the heat transfer and flow in solar energy and bioenergy systems, specifically for Thermal Energy Storage (TES) systems in Concentrated Solar Power (CSP) plants and open-channel algal culture raceways for biofuel production. The first part of this dissertation is the discussion about mathematical modeling, numerical simulation and experimental investigation of solar TES system. First of all, in order to accurately and efficiently simulate the conjugate heat transfer between Heat Transfer Fluid (HTF) and filler material in four different solid-fluid TES configurations, formulas of an e?ective heat transfer coe?cient were theoretically developed and presented by extending the validity of Lumped Capacitance Method (LCM) to large Biot number, as well as verifications/validations to this simplified model. Secondly, to provide design guidelines for TES system in CSP plant using Phase Change Materials (PCM), a general storage tank volume sizing strategy and an energy storage startup strategy were proposed using the enthalpy-based 1D transient model. Then experimental investigations were conducted to explore a novel thermal storage material. The thermal storage performances were also compared between this novel storage material and concrete at a temperature range from 400 °C to 500 °C. It is recommended to apply this novel thermal storage material to replace concrete at high operating temperatures in sensible heat TES systems. The second part of this dissertation mainly focuses on the numerical and experimental study of an open-channel algae

  1. Optimal aeroassisted coplanar orbital transfer using an energy model

    Science.gov (United States)

    Halyo, Nesim; Taylor, Deborah B.

    1989-01-01

    The atmospheric portion of the trajectories for the aeroassisted coplanar orbit transfer was investigated. The equations of motion for the problem are expressed using reduced order model and total vehicle energy, kinetic plus potential, as the independent variable rather than time. The order reduction is achieved analytically without an approximation of the vehicle dynamics. In this model, the problem of coplanar orbit transfer is seen as one in which a given amount of energy must be transferred from the vehicle to the atmosphere during the trajectory without overheating the vehicle. An optimal control problem is posed where a linear combination of the integrated square of the heating rate and the vehicle drag is the cost function to be minimized. The necessary conditions for optimality are obtained. These result in a 4th order two-point-boundary-value problem. A parametric study of the optimal guidance trajectory in which the proportion of the heating rate term versus the drag varies is made. Simulations of the guidance trajectories are presented.

  2. A new rapid method for rockfall energies and distances estimation

    Science.gov (United States)

    Giacomini, Anna; Ferrari, Federica; Thoeni, Klaus; Lambert, Cedric

    2016-04-01

    and distances at the base to block and slope features. The validation of the proposed approach was conducted by comparing predictions to experimental data collected in the field and gathered from the scientific literature. The method can be used for both natural and constructed slopes and easily extended to more complicated and articulated slope geometries. The study shows its great potential for a quick qualitative hazard assessment providing indication about impact energy and horizontal distance of the first impact at the base of a rock cliff. Nevertheless, its application cannot substitute a more detailed quantitative analysis required for site-specific design of mitigation measures. Acknowledgements The authors gratefully acknowledge the financial support of the Australian Coal Association Research Program (ACARP). References Dorren, L.K.A. (2003) A review of rockfall mechanics and modelling approaches, Progress in Physical Geography 27(1), 69-87. Agliardi, F., Crosta, G.B., Frattini, P. (2009) Integrating rockfall risk assessment and countermeasure design by 3D modelling techniques. Natural Hazards and Earth System Sciences 9(4), 1059-1073. Ferrari, F., Thoeni, K., Giacomini, A., Lambert, C. (2016) A rapid approach to estimate the rockfall energies and distances at the base of rock cliffs. Georisk, DOI: 10.1080/17499518.2016.1139729.

  3. Boosting infrared energy transfer in 3D nanoporous gold antennas.

    Science.gov (United States)

    Garoli, D; Calandrini, E; Bozzola, A; Ortolani, M; Cattarin, S; Barison, S; Toma, A; De Angelis, F

    2017-01-05

    The applications of plasmonics to energy transfer from free-space radiation to molecules are currently limited to the visible region of the electromagnetic spectrum due to the intrinsic optical properties of bulk noble metals that support strong electromagnetic field confinement only close to their plasma frequency in the visible/ultraviolet range. In this work, we show that nanoporous gold can be exploited as a plasmonic material for the mid-infrared region to obtain strong electromagnetic field confinement, co-localized with target molecules into the nanopores and resonant with their vibrational frequency. The effective optical response of the nanoporous metal enables the penetration of optical fields deep into the nanopores, where molecules can be loaded thus achieving a more efficient light-matter coupling if compared to bulk gold. In order to realize plasmonic resonators made of nanoporous gold, we develop a nanofabrication method based on polymeric templates for metal deposition and we obtain antenna arrays resonating at mid-infrared wavelengths selected by design. We then coat the antennas with a thin (3 nm) silica layer acting as the target dielectric layer for optical energy transfer. We study the strength of the light-matter coupling at the vibrational absorption frequency of silica at 1240 cm-1 through the analysis of the experimental Fano lineshape that is benchmarked against identical structures made of bulk gold. The boost in the optical energy transfer from free-space mid-infrared radiation to molecular vibrations in nanoporous 3D nanoantenna arrays can open new application routes for plasmon-enhanced physical-chemical reactions.

  4. Single particle tracking and single molecule energy transfer

    CERN Document Server

    Bräuchle, Christoph; Michaelis, Jens

    2009-01-01

    Closing a gap in the literature, this handbook gathers all the information on single particle tracking and single molecule energy transfer. It covers all aspects of this hot and modern topic, from detecting virus entry to membrane diffusion, and from protein folding using spFRET to coupled dye systems, as well recent achievements in the field. Throughout, the first-class editors and top international authors present content of the highest quality, making this a must-have for physical chemists, spectroscopists, molecular physicists and biochemists.

  5. Cell Microtubules as Cavities Quantum Coherence and Energy Transfer?

    CERN Document Server

    Mavromatos, Nikolaos E

    2000-01-01

    A model is presented for dissipationless energy transfer in cell microtubules due to quantum coherent states. The model is based on conjectured (hydrated) ferroelectric properties of microtubular arrangements. Ferroelectricity is essential in providing the necessary isolation against thermal losses in thin interior regions, full of ordered water, near the tubulin dimer walls of the microtubule. These play the role of cavity regions, which are similar to electromagnetic cavities of quantum optics. As a result, the formation of (macroscopic) quantum coherent states of electric dipoles on the tubulin dimers may occur. Some experiments, inspired by quantum optics, are suggested for the falsification of this scenario.

  6. Nanoparticles for heat transfer and thermal energy storage

    Science.gov (United States)

    Singh, Dileep; Cingarapu, Sreeram; Timofeeva, Elena V.; Moravek, Michael

    2015-07-14

    An article of manufacture and method of preparation thereof. The article of manufacture and method of making the article includes an eutectic salt solution suspensions and a plurality of nanocrystalline phase change material particles having a coating disposed thereon and the particles capable of undergoing the phase change which provides increase in thermal energy storage. In addition, other articles of manufacture can include a nanofluid additive comprised of nanometer-sized particles consisting of copper decorated graphene particles that provide advanced thermal conductivity to heat transfer fluids.

  7. 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.

  8. Power Loss Analysis and Comparison of Segmented and Unsegmented Energy Coupling Coils for Wireless Energy Transfer.

    Science.gov (United States)

    Tang, Sai Chun; McDannold, Nathan J

    2015-03-01

    This paper investigated the power losses of unsegmented and segmented energy coupling coils for wireless energy transfer. Four 30-cm energy coupling coils with different winding separations, conductor cross-sectional areas, and number of turns were developed. The four coils were tested in both unsegmented and segmented configurations. The winding conduction and intrawinding dielectric losses of the coils were evaluated individually based on a well-established lumped circuit model. We found that the intrawinding dielectric loss can be as much as seven times higher than the winding conduction loss at 6.78 MHz when the unsegmented coil is tightly wound. The dielectric loss of an unsegmented coil can be reduced by increasing the winding separation or reducing the number of turns, but the power transfer capability is reduced because of the reduced magnetomotive force. Coil segmentation using resonant capacitors has recently been proposed to significantly reduce the operating voltage of a coil to a safe level in wireless energy transfer for medical implants. Here, we found that it can naturally eliminate the dielectric loss. The coil segmentation method and the power loss analysis used in this paper could be applied to the transmitting, receiving, and resonant coils in two- and four-coil energy transfer systems.

  9. Crossed-beam energy transfer in direct-drive implosions

    Energy Technology Data Exchange (ETDEWEB)

    Seka, W; Edgell, D H; Michel, D T; Froula, D H; Goncharov, V N; Craxton, R S; Divol, L; Epstein, R; Follett, R; Kelly, J H; Kosc, T Z; Maximov, A V; McCrory, R L; Meyerhofer, D D; Michel, P; Myatt, J F; Sangster, T C; Shvydky, A; Skupsky, S

    2012-05-22

    Direct-drive-implosion experiments on the OMEGA laser [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] have showed discrepancies between simulations of the scattered (non-absorbed) light levels and measured ones that indicate the presence of a mechanism that reduces laser coupling efficiency by 10%-20%. This appears to be due to crossed-beam energy transfer (CBET) that involves electromagnetic-seeded, low-gain stimulated Brillouin scattering. CBET scatters energy from the central portion of the incoming light beam to outgoing light, reducing the laser absorption and hydrodynamic efficiency of implosions. One-dimensional hydrodynamic simulations including CBET show good agreement with all observables in implosion experiments on OMEGA. Three strategies to mitigate CBET and improve laser coupling are considered: the use of narrow beams, multicolor lasers, and higher-Z ablators. Experiments on OMEGA using narrow beams have demonstrated improvements in implosion performance.

  10. Crossed-beam energy transfer in direct-drive implosions

    Energy Technology Data Exchange (ETDEWEB)

    Igumenshchev, I. V.; Seka, W.; Edgell, D. H.; Michel, D. T.; Froula, D. H.; Craxton, R. S.; Epstein, R.; Follett, R.; Kelly, J. H.; Kosc, T. Z.; Myatt, J. F.; Sangster, T. C.; Shvydky, A.; Skupsky, S.; Stoeckl, C. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Goncharov, V. N.; Maximov, A. V. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Department of Mechanical Engineering, University of Rochester, Rochester, New York 14623 (United States); Divol, L.; Michel, P. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); McCrory, R. L. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Department of Mechanical Engineering, University of Rochester, Rochester, New York 14623 (United States); Department of Physics and Astronomy, University of Rochester, Rochester, New York 14623 (United States); and others

    2012-05-15

    Direct-drive-implosion experiments on the OMEGA laser [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] have showed discrepancies between simulations of the scattered (non-absorbed) light levels and measured ones that indicate the presence of a mechanism that reduces laser coupling efficiency by 10%-20%. This appears to be due to crossed-beam energy transfer (CBET) that involves electromagnetic-seeded, low-gain stimulated Brillouin scattering. CBET scatters energy from the central portion of the incoming light beam to outgoing light, reducing the laser absorption and hydrodynamic efficiency of implosions. One-dimensional hydrodynamic simulations including CBET show good agreement with all observables in implosion experiments on OMEGA. Three strategies to mitigate CBET and improve laser coupling are considered: the use of narrow beams, multicolor lasers, and higher-Z ablators. Experiments on OMEGA using narrow beams have demonstrated improvements in implosion performance.

  11. Effect of high linear energy transfer radiation on biological membranes

    Energy Technology Data Exchange (ETDEWEB)

    Choudhary, D.; Srivastava, M.; Kale, R.K. [Radiation Biology Lab., Jawaharlal Nehru Univ., New Delhi (India); Sarma, A. [Nuclear Science Centre, New Delhi (India)

    1998-10-01

    Cellular membranes are vital elements, and their integrity is extremely essential for the viability of the cells. We studied the effects of high linear energy transfer (LET) radiation on the membranes. Rabbit erythrocytes (1 x 10{sup 7} cells/ml) and microsomes (0.6 mg protein/ml) prepared from liver of rats were irradiated with {sup 7}Li ions of energy 6.42 MeV/u and {sup 16}O ions of energy 4.25 MeV/u having maximum LET values of 354 keV/{mu}m and 1130 keV/{mu}m, respectively. {sup 7}Li- and {sup 16}O-induced microsomal lipid peroxidation was found to increase with fluence. The {sup 16}O ions were more effective than {sup 7}Li ions, which could be due to the denser energy distribution in the track and the yield of free radicals. These findings suggested that the biological membranes could be peroxidized on exposure to high-LET radiation. Inhibition of the lipid peroxidation was observed in the presence of a membrane-active drug, chlorpromazine (CPZ), which could be due to scavenging of free radicals (mainly HO. and ROO.), electron donation, and hydrogen transfer reactions. The {sup 7}Li and {sup 16}O ions also induced hemolysis in erythrocytes. The extent of hemolysis was found to be a function of time and fluence, and showed a characteristic sigmoidal pattern. The {sup 16}O ions were more effective in the lower fluence range than {sup 7}Li ions. These results were compared with lipid peroxidation and hemolysis induced by gamma-radiation. (orig.) With 7 figs., 3 tabs., 30 refs.

  12. Light harvesting via energy transfer in the dye solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Siegers, Conrad

    2007-11-09

    The PhD-thesis ''Light Harvesting via Energy Transfer in the Dye Solar Cell'' (University of Freiburg, July 2007) describes the conceptual design, synthesis and testing of energy donor acceptor sensitizers for the dye solar cell (DSC). Under monochromatic illumination solar cells sensitized with the novel donor acceptor systems revealed a higher power conversion efficiency than cells containing exclusively the acceptor component. The following approach led to this conclusion: (i) the choice of suitable chromophores as energy donor and acceptor moieties according to the Foerster-theory, (ii) the synthesis of different donor acceptor systems, (iii) the development of a methodology allowing the quantification of energy transfer within dye solar cells, and (iv) the evaluation of characteristics of DSCs that were sensitized with the different donor acceptor systems. The acceptor chromophores used in this work were derived from [Ru(dcbpy)2acac]Cl (dcbpy = 4,4'-dicarboxy-2,2'-bipyridin, acac = acetylacetonato). This complex offered the opportunity to introduce substituents at the acac-ligand's terminal CH3 groups without significantly affecting its excellent photoelectrochemical properties. Alkylated 4-amino-1,8-naphthalimides (termed Fluorols in the following) were used as energy donor chromophores. This class of compounds fulfils the requirements for efficient energy transfer to [Ru(dcbpy)2acac]Cl. Covalently linking donor and acceptor chromophores to one another was achieved by two different concepts. A dyad comprising one donor and one acceptor chromophore was synthesized by subsequent hydrosilylation steps of an olefin-bearing donor and an acceptor precursor to the dihydrosilane HSiMe2-CH2CH2-SiMe2H. A series of polymers comprising multiple donor and acceptor units was made by the addition of alkyne-bearing chromophores to hyperbranched polyglycerol azide (''Click-chemistry''). In this series the donor acceptor

  13. Heat transfer and energy efficiency in infrared paper dryers

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, Magnus

    1999-11-01

    Infrared (IR) dryers are widely used in the paper industry, mainly in the production of coated paper grades. The thesis deals with various aspects of heat transfer and energy use in infrared heaters and dryers as employed in the paper industry. Both gas-fired and electric IR dryers are considered and compared. The thesis also provides an introduction to infrared heaters and infrared drying, including a review of recent literature in the field. The transport of thermal radiation inside a paper sheet was investigated and different IR dryers were compared in terms of their ability to transfer energy to the internal parts of a paper sheet. Although there were evident differences in the absorption of radiation between gas-fired and electric IR dryers, the distinction was found not to be as important as has generally been believed. The main differences appeared to be due to the choice of a one- or a two-sided dryer solution, rather than the spectral distributions emitted by the dryers. A method for evaluating the radiation efficiency of IR heaters was proposed. An electric IR heater was evaluated in the laboratory. The radiation efficiency of the heater was shown to be strongly dependent on the power level. The maximum efficiency, found at high power level, was close to 60 %. A procedure for evaluation of the total energy transfer efficiency of an infrared paper dryer was proposed and used in the evaluation of an electric IR dryer operating in an industrial coating machine. The efficiency of the dryer was roughly 40 %. A model for an electric IR heater was developed. The model includes non-grey radiative heat transfer between the different parts of the heater, as well as conduction in reflector material and convective cooling of the surfaces. Using IR module voltage as the only input, model predictions of temperatures and heat flux were found to agree well with experimental data both at steady state and under transient conditions. The model was also extended to include

  14. Energy transfer from lower energy to higher-energy electrons mediated by whistler waves in the radiation belts

    Science.gov (United States)

    Shklyar, D. R.

    2017-01-01

    We study the problem of energy exchange between waves and particles, which leads to energization of the latter, in an unstable plasma typical of the radiation belts. The ongoing Van Allen Probes space mission brought this problem among the most discussed in space physics. A free energy which is present in an unstable plasma provides the indispensable condition for energy transfer from lower energy particles to higher-energy particles via resonant wave-particle interaction. This process is studied in detail by the example of electron interactions with whistler mode wave packets originated from lightning-induced emission. We emphasize that in an unstable plasma, the energy source for electron energization is the energy of other particles, rather than the wave energy as is often assumed. The way by which the energy is transferred from lower energy to higher-energy particles includes two processes that operate concurrently, in the same space-time domain, or sequentially, in different space-time domains, in which a given wave packet is located. In the first process, one group of resonant particles gives the energy to the wave. The second process consists in wave absorption by another group of resonant particles, whose energy therefore increases. We argue that this mechanism represents an efficient means of electron energization in the radiation belts.

  15. Elementary Energy Transfer Pathways in Allochromatium vinosum Photosynthetic Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Lüer, Larry; Carey, Anne-Marie; Henry, Sarah; Maiuri, Margherita; Hacking, Kirsty; Polli, Dario; Cerullo, Giulio; Cogdell, Richard J.

    2015-11-01

    Allochromatium vinosum (formerly Chromatium vinosum) purple bacteria are known to adapt their light-harvesting strategy during growth according to environmental factors such as temperature and average light intensity. Under low light illumination or low ambient temperature conditions, most of the LH2 complexes in the photosynthetic membranes form a B820 exciton with reduced spectral overlap with LH1. To elucidate the reason for this light and temperature adaptation of the LH2 electronic structure, we performed broadband femtosecond transient absorption spectroscopy as a function of excitation wavelength in A. vinosum membranes. A target analysis of the acquired data yielded individual rate constants for all relevant elementary energy transfer (ET) processes. We found that the ET dynamics in high-light-grown membranes was well described by a homogeneous model, with forward and backward rate constants independent of the pump wavelength. Thus, the overall B800→B850→B890→ Reaction Center ET cascade is well described by simple triexponential kinetics. In the low-light-grown membranes, we found that the elementary backward transfer rate constant from B890 to B820 was strongly reduced compared with the corresponding constant from B890 to B850 in high-light-grown samples. The ET dynamics of low-light-grown membranes was strongly dependent on the pump wavelength, clearly showing that the excitation memory is not lost throughout the exciton lifetime. The observed pump energy dependence of the forward and backward ET rate constants suggests exciton diffusion via B850→ B850 transfer steps, making the overall ET dynamics nonexponential. Our results show that disorder plays a crucial role in our understanding of low-light adaptation in A. vinosum.

  16. Elementary Energy Transfer Pathways in Allochromatium vinosum Photosynthetic Membranes

    Science.gov (United States)

    Lüer, Larry; Carey, Anne-Marie; Henry, Sarah; Maiuri, Margherita; Hacking, Kirsty; Polli, Dario; Cerullo, Giulio; Cogdell, Richard J.

    2015-01-01

    Allochromatium vinosum (formerly Chromatium vinosum) purple bacteria are known to adapt their light-harvesting strategy during growth according to environmental factors such as temperature and average light intensity. Under low light illumination or low ambient temperature conditions, most of the LH2 complexes in the photosynthetic membranes form a B820 exciton with reduced spectral overlap with LH1. To elucidate the reason for this light and temperature adaptation of the LH2 electronic structure, we performed broadband femtosecond transient absorption spectroscopy as a function of excitation wavelength in A. vinosum membranes. A target analysis of the acquired data yielded individual rate constants for all relevant elementary energy transfer (ET) processes. We found that the ET dynamics in high-light-grown membranes was well described by a homogeneous model, with forward and backward rate constants independent of the pump wavelength. Thus, the overall B800→B850→B890→ Reaction Center ET cascade is well described by simple triexponential kinetics. In the low-light-grown membranes, we found that the elementary backward transfer rate constant from B890 to B820 was strongly reduced compared with the corresponding constant from B890 to B850 in high-light-grown samples. The ET dynamics of low-light-grown membranes was strongly dependent on the pump wavelength, clearly showing that the excitation memory is not lost throughout the exciton lifetime. The observed pump energy dependence of the forward and backward ET rate constants suggests exciton diffusion via B850→ B850 transfer steps, making the overall ET dynamics nonexponential. Our results show that disorder plays a crucial role in our understanding of low-light adaptation in A. vinosum. PMID:26536265

  17. Photophysical properties and energy transfer mechanism of PFO/Fluorol 7GA hybrid thin films

    Energy Technology Data Exchange (ETDEWEB)

    Al-Asbahi, Bandar Ali, E-mail: alasbahibandar@gmail.com [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Department of Physics, Faculty of Science, Sana' a University (Yemen); Jumali, Mohammad Hafizuddin Haji, E-mail: hafizhj@ukm.my [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Yap, Chi Chin; Flaifel, Moayad Husein [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Salleh, Muhamad Mat [Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia)

    2013-10-15

    Photophysical properties of poly (9,9′-di-n-octylfluorenyl-2.7-diyl) (PFO)/2-butyl-6- (butylamino)benzo [de] isoquinoline-1,3-dione (Fluorol 7GA) and energy transfer between them have been investigated. In this work, both PFO and Fluorol 7GA act as donor and acceptor, respectively. Based on the absorption and luminescence measurements, the photophysical and energy transfer properties such as fluorescence quantum yield (Φ{sub f}), fluorescence lifetime (τ), radiative rate constant (k{sub r}), non-radiative rate constant (k{sub nr}), quenching rate constant (k{sub SV}), energy transfer rate constant (k{sub ET}), energy transfer probability (P{sub DA}), energy transfer efficiency (η), critical concentration of acceptor (C{sub o}), energy transfer time (τ{sub ET}) and critical distance of energy transfer (R{sub o}) were calculated. Large values of k{sub SV}, k{sub ET} and R{sub o} suggested that Förster-type energy transfer was the dominant mechanism for the energy transfer between the excited donor and ground state acceptor molecules. It was observed that the Förster energy transfer together with the trapping process are crucial for performance improvement in ITO/(PFO/Fluorol7GA)/Al device. -- Highlights: • The efficient of energy transfer from PFO to Fluorol 7GA was evidenced. • The resonance energy transfer (Förster type) is the dominant mechanism. • Hsu et al. model was used to calculate Φ{sub f}, τ, k{sub r} and k{sub nr} of PFO thin film. • Several of the photophysical and energy transfer properties were calculated. • Trapping process and Förster energy transfer led to improve the device performance.

  18. Rapid Impedance Spectrum Measurements for State-of-Health Assessment of Energy Storage Devices

    Energy Technology Data Exchange (ETDEWEB)

    Jon P. Christophersen; John L. Morrison; Chester G. Motloch; William H. Morrison

    2012-04-01

    Harmonic compensated synchronous detection (HCSD) is a technique that can be used to measure wideband impedance spectra within seconds based on an input sum-of-sines signal having a frequency spread separated by harmonics. The battery (or other energy storage device) is excited with a sum-of-sines current signal that has a duration of at least one period of the lowest frequency. The voltage response is then captured and synchronously detected at each frequency of interest to determine the impedance spectra. This technique was successfully simulated using a simplified battery model and then verified with commercially available Sanyo lithium-ion cells. Simulations revealed the presence of a start-up transient effect when only one period of the lowest frequency is included in the excitation signal. This transient effect appears to only influence the low-frequency impedance measurements and can be reduced when a longer input signal is used. Furthermore, lithium-ion cell testing has indicated that the transient effect does not seem to impact the charge transfer resistance in the mid-frequency region. The degradation rates for the charge transfer resistance measured from the HCSD technique were very similar to the changes observed from standardized impedance spectroscopy methods. Results from these studies, therefore, indicate that HCSD is a viable, rapid alternative approach to acquiring impedance spectra.

  19. Optimal dephasing for ballistic energy transfer in disordered linear chains

    Science.gov (United States)

    Zhang, Yang; Celardo, G. Luca; Borgonovi, Fausto; Kaplan, Lev

    2017-11-01

    We study the interplay between dephasing, disorder, and coupling to a sink on transport efficiency in a one-dimensional chain of finite length N , and in particular the beneficial or detrimental effect of dephasing on transport. The excitation moves along the chain by coherent nearest-neighbor hopping Ω , under the action of static disorder W and dephasing γ . The last site is coupled to an external acceptor system (sink), where the excitation can be trapped with a rate Γtrap. While it is known that dephasing can help transport in the localized regime, here we show that dephasing can enhance energy transfer even in the ballistic regime. Specifically, in the localized regime we recover previous results, where the optimal dephasing is independent of the chain length and proportional to W or W2/Ω . In the ballistic regime, the optimal dephasing decreases as 1 /N or 1 /√{N } , respectively, for weak and moderate static disorder. When focusing on the excitation starting at the beginning of the chain, dephasing can help excitation transfer only above a critical value of disorder Wcr, which strongly depends on the sink coupling strength Γtrap. Analytic solutions are obtained for short chains.

  20. Unravelling radiative energy transfer in solid-state lighting

    Science.gov (United States)

    Melikov, Rustamzhon; Press, Daniel Aaron; Ganesh Kumar, Baskaran; Sadeghi, Sadra; Nizamoglu, Sedat

    2018-01-01

    Today, a wide variety of organic and inorganic luminescent materials (e.g., phosphors, quantum dots, etc.) are being used for lighting and new materials (e.g., graphene, perovskite, etc.) are currently under investigation. However, the understanding of radiative energy transfer is limited, even though it is critical to understand and improve the performance levels of solid-state lighting devices. In this study, we derived a matrix approach that includes absorption, reabsorption, inter-absorption and their iterative and combinatorial interactions for one and multiple types of fluorophores, which is simplified to an analytical matrix. This mathematical approach gives results that agree well with the measured spectral and efficiency characteristics of color-conversion light-emitting diodes. Moreover, it also provides a deep physical insight by uncovering the entire radiative interactions and their contribution to the output optical spectrum. The model is universal and applicable for all kinds of fluorophores.

  1. Large impact of reorganization energy on photovoltaic conversion due to interfacial charge-transfer transitions.

    Science.gov (United States)

    Fujisawa, Jun-ichi

    2015-05-14

    Interfacial charge-transfer (ICT) transitions are expected to be a novel charge-separation mechanism for efficient photovoltaic conversion featuring one-step charge separation without energy loss. Photovoltaic conversion due to ICT transitions has been investigated using several TiO2-organic hybrid materials that show organic-to-inorganic ICT transitions in the visible region. In applications of ICT transitions to photovoltaic conversion, there is a significant problem that rapid carrier recombination is caused by organic-inorganic electronic coupling that is necessary for the ICT transitions. In order to solve this problem, in this work, I have theoretically studied light-to-current conversions due to the ICT transitions on the basis of the Marcus theory with density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. An apparent correlation between the reported incident photon-to-current conversion efficiencies (IPCE) and calculated reorganization energies was clearly found, in which the IPCE increases with decreasing the reorganization energy consistent with the Marcus theory in the inverted region. This activation-energy dependence was systematically explained by the equation formulated by the Marcus theory based on a simple excited-state kinetic scheme. This result indicates that the reduction of the reorganization energy can suppress the carrier recombination and enhance the IPCE. The reorganization energy is predominantly governed by the structural change in the chemical-adsorption moiety between the ground and ICT excited states. This work provides crucial knowledge for efficient photovoltaic conversion due to ICT transitions.

  2. Variety in excitation energy transfer processes from phycobilisomes to photosystems I and II.

    Science.gov (United States)

    Ueno, Yoshifumi; Aikawa, Shimpei; Niwa, Kyosuke; Abe, Tomoko; Murakami, Akio; Kondo, Akihiko; Akimoto, Seiji

    2017-09-01

    The light-harvesting antennas of oxygenic photosynthetic organisms capture light energy and transfer it to the reaction centers of their photosystems. The light-harvesting antennas of cyanobacteria and red algae, called phycobilisomes (PBSs), supply light energy to both photosystem I (PSI) and photosystem II (PSII). However, the excitation energy transfer processes from PBS to PSI and PSII are not understood in detail. In the present study, the energy transfer processes from PBS to PSs in various cyanobacteria and red algae were examined in vivo by selectively exciting their PSs or PBSs, and measuring the resulting picosecond to nanosecond time-resolved fluorescences. By observing the delayed fluorescence spectrum of PBS-selective excitation in Arthrospira platensis, we demonstrated that energy transfer from PBS to PSI via PSII (PBS→PSII→PSI transfer) occurs even for PSI trimers. The contribution of PBS→PSII→PSI transfer was species dependent, being largest in the wild-type of red alga Pyropia yezoensis (formerly Porphyra yezoensis) and smallest in Synechococcus sp. PCC 7002. Comparing the time-resolved fluorescence after PSs- and PBS-selective excitation, we revealed that light energy flows from CP43 to CP47 by energy transfer between the neighboring PSII monomers in PBS-PSII supercomplexes. We also suggest two pathways of energy transfer: direct energy transfer from PBS to PSI (PBS→PSI transfer) and indirect transfer through PSII (PBS→PSII→PSI transfer). We also infer that PBS→PSI transfer conveys light energy to a lower-energy red chlorophyll than PBS→PSII→PSI transfer.

  3. Incident energy transfer equation and its solution by collocation spectral method for one-dimensional radiative heat transfer

    Science.gov (United States)

    Hu, Zhang-Mao; Tian, Hong; Li, Ben-Wen; Zhang, Wei; Yin, Yan-Shan; Ruan, Min; Chen, Dong-Lin

    2017-10-01

    The ray-effect is a major discretization error in the approximate solution method for the radiative transfer equation (RTE). To overcome this problem, the incident energy transfer equation (IETE) is proposed. The incident energy, instead of radiation intensity, is obtained by directly solving this new equation. Good numerical properties are found for the incident energy transfer equation. To show the properties of numerical solution, the collocation spectral method (CSM) is employed to solve the incident energy transfer equation. Three test cases are taken into account to verify the performance of the incident energy transfer equation. The result shows that the radiative heat flux obtained based on IETE is much more accurate than that based on RTE, which means that the IETE is very effective in eliminating the impacts of ray-effect on the heat flux. However, on the contrary, the radiative intensity obtained based on IETE is less accurate than that based on RTE due to the ray-effect. So, this equation is more suitable for those radiative heat transfer problems, in which the radiation heat flux and incident energy are needed rather than the radiation intensity.

  4. Proton Linear Energy Transfer measurement using Emulsion Cloud Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jae-ik [Proton Therapy Center, National Cancer Center (Korea, Republic of); Division of Heavy Ion Clinical Research, Korea Institute of Radiological & Medical Sciences (KIRAMS), Seoul (Korea, Republic of); Park, Seyjoon [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University, School of Medicine, Seoul (Korea, Republic of); Kim, Haksoo; Kim, Meyoung [Proton Therapy Center, National Cancer Center (Korea, Republic of); Jeong, Chiyoung [Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Cho, Sungkoo [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University, School of Medicine, Seoul (Korea, Republic of); Lim, Young Kyung; Shin, Dongho [Proton Therapy Center, National Cancer Center (Korea, Republic of); Lee, Se Byeong, E-mail: sblee@ncc.re.kr [Proton Therapy Center, National Cancer Center (Korea, Republic of); Morishima, Kunihiro; Naganawa, Naotaka; Sato, Osamu [Department of Physics, Nagoya University, Nagoya (Japan); Kwak, Jungwon [Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Kim, Sung Hyun [Center for Underground Physics, Institute for Basic Science (IBS), Daejeon (Korea, Republic of); Cho, Jung Sook [Department of refinement education, Dongseo University, Busan (Korea, Republic of); Ahn, Jung Keun [Department of Physics, Korea University, Seoul (Korea, Republic of); Kim, Ji Hyun; Yoon, Chun Sil [Gyeongsang National University, Jinju (Korea, Republic of); Incerti, Sebastien [CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Université Bordeaux 1, CENBG, UMR 5797, F-33170 Gradignan (France)

    2015-04-15

    This study proposes to determine the correlation between the Volume Pulse Height (VPH) measured by nuclear emulsion and Linear Energy Transfer (LET) calculated by Monte Carlo simulation based on Geant4. The nuclear emulsion was irradiated at the National Cancer Center (NCC) with a therapeutic proton beam and was installed at 5.2 m distance from the beam nozzle structure with various thicknesses of water-equivalent material (PMMA) blocks to position with specific positions along the Bragg curve. After the beam exposure and development of the emulsion films, the films were scanned by S-UTS developed in Nagoya University. The proton tracks in the scanned films were reconstructed using the ‘NETSCAN’ method. Through this procedure, the VPH can be derived from each reconstructed proton track at each position along the Bragg curve. The VPH value indicates the magnitude of energy loss in proton track. By comparison with the simulation results obtained using Geant4, we found the correlation between the LET calculated by Monte Carlo simulation and the VPH measured by the nuclear emulsion.

  5. Proton Linear Energy Transfer measurement using Emulsion Cloud Chamber

    Science.gov (United States)

    Shin, Jae-ik; Park, Seyjoon; Kim, Haksoo; Kim, Meyoung; Jeong, Chiyoung; Cho, Sungkoo; Lim, Young Kyung; Shin, Dongho; Lee, Se Byeong; Morishima, Kunihiro; Naganawa, Naotaka; Sato, Osamu; Kwak, Jungwon; Kim, Sung Hyun; Cho, Jung Sook; Ahn, Jung Keun; Kim, Ji Hyun; Yoon, Chun Sil; Incerti, Sebastien

    2015-04-01

    This study proposes to determine the correlation between the Volume Pulse Height (VPH) measured by nuclear emulsion and Linear Energy Transfer (LET) calculated by Monte Carlo simulation based on Geant4. The nuclear emulsion was irradiated at the National Cancer Center (NCC) with a therapeutic proton beam and was installed at 5.2 m distance from the beam nozzle structure with various thicknesses of water-equivalent material (PMMA) blocks to position with specific positions along the Bragg curve. After the beam exposure and development of the emulsion films, the films were scanned by S-UTS developed in Nagoya University. The proton tracks in the scanned films were reconstructed using the 'NETSCAN' method. Through this procedure, the VPH can be derived from each reconstructed proton track at each position along the Bragg curve. The VPH value indicates the magnitude of energy loss in proton track. By comparison with the simulation results obtained using Geant4, we found the correlation between the LET calculated by Monte Carlo simulation and the VPH measured by the nuclear emulsion.

  6. On Measuring Cosmic Ray Energy Spectra with the Rapidity Distributions

    Science.gov (United States)

    Bashindzhagyan, G.; Adams, J.; Chilingarian, A.; Drury, L.; Egorov, N.; Golubkov, S.; Korotkova, N.; Panasyuk, M.; Podorozhnyi, D.; Procqureur, J.

    2000-01-01

    An important goal of cosmic ray research is to measure the elemental energy spectra of galactic cosmic rays up to 10(exp 16) eV. This goal cannot be achieved with an ionization calorimeter because the required instrument is too massive for space flight. An alternate method will be presented. This method is based on measuring the primary particle energy by determining the angular distribution of secondaries produced in a target layer. The proposed technique can be used over a wide range of energies (10 (exp 11) -10 (exp 16) eV) and gives an energy resolution of 60% or better. Based on this technique, a conceptual design for a new instrument (KLEM) will be presented. Due to its light weight, this instrument can have a large aperture enabling the direct measurement of cosmic rays to 1016 eV.

  7. Exploiting energy transfer in hybrid metal and semiconductor nanoparticle systems for biosensing and energy harvesting

    Energy Technology Data Exchange (ETDEWEB)

    Mayilo, Sergiy

    2009-06-19

    In this work, gold and semiconductor nanoparticles are used as building blocks for nanostructures, in which energy transfer is investigated. Fluorescence quenching by gold nanoparticles is investigated and used to develop novel immunoassays for medically relevant molecules. The influence of gold nanoparticles on radiative and non-radiative rates of Cy3 and Cy3B dyes is studied here. A competitive, homogeneous immunoassay for digoxigenin and digoxin, a drug used to cure heart diseases, is developed. The assay has a limit of detection of 0.5 nM in buffer and 50 nM in serum. Time resolved spectroscopy reveals that the quenching is due to energy transfer with an efficiency of 70%. A homogeneous sandwich immunoassay for cardiac troponin T, an indicator of damage to the heart muscle, is developed. Gold nanoparticles and fluorophores are functionalized with anti-troponin T antibodies. In the presence of troponin T the nanoparticles and fluorophores form a sandwich structure, in which the dye fluorescence is quenched by a gold nanoparticle. The limit of detection of the immunoassay in buffer is 0.02 nM and 0.11 nM in serum. Energy transfer is demonstrated in clusters of CdTe nanocrystals assembled using three methods. In the first method, clusters of differently-sized water soluble CdTe nanocrystals capped by negatively charged mercaptoacid stabilizers are produced through electrostatic interactions with positively charged Ca{sup 2+} cations. The two other methods employ covalent binding through dithiols and thiolated DNA as linkers between nanocrystals. Energy transfer from smaller nanocrystals to larger nanocrystals in aggregates is demonstrated by means of steady-state and time-resolved photoluminescence spectroscopy, paving the way for nanocrystal-based light harvesting structures in solution. Multi-shell onion-like CdSe/ZnS/CdSe/ZnS nanocrystals are presented. The shade of the white light can be controlled by annealing the particles. Evidence for intra

  8. 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.

  9. Energy transfer rate in double-layer graphene systems: Linear regime

    Energy Technology Data Exchange (ETDEWEB)

    Bahrami, B., E-mail: b_bahrami@sbu.ac.ir [Department of Physics, Shahid Beheshti University, G. C., Evin, 1983963113, Tehran (Iran, Islamic Republic of); Vazifehshenas, T., E-mail: t-vazifeh@sbu.ac.ir [Department of Physics, Shahid Beheshti University, G. C., Evin, 1983963113, Tehran (Iran, Islamic Republic of)

    2012-10-15

    We theoretically investigate the energy transfer phenomenon in a double-layer graphene (DLG) system. We use the balance equation approach in linear regime and random phase approximation screening function to obtain energy transfer rates at different electron temperatures, densities and interlayer spacings. We find that the rate of energy transfer in the DLG is qualitatively similar to that obtained in the double-layer two-dimensional electron gas but its values are an order of magnitude greater. Also, at large electron temperature differences between two graphene layers, the electron density dependence of energy transfer is significantly different, particularly in case of unequal electron densities.

  10. 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

  11. 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.

  12. 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.

  13. Validation of Contamination Control in Rapid Transfer Port Chambers for Pharmaceutical Manufacturing Processes.

    Science.gov (United States)

    Hu, Shih-Cheng; Shiue, Angus; Liu, Han-Yang; Chiu, Rong-Ben

    2016-11-12

    There is worldwide concern with regard to the adverse effects of drug usage. However, contaminants can gain entry into a drug manufacturing process stream from several sources such as personnel, poor facility design, incoming ventilation air, machinery and other equipment for production, etc. In this validation study, we aimed to determine the impact and evaluate the contamination control in the preparation areas of the rapid transfer port (RTP) chamber during the pharmaceutical manufacturing processes. The RTP chamber is normally tested for airflow velocity, particle counts, pressure decay of leakage, and sterility. The air flow balance of the RTP chamber is affected by the airflow quantity and the height above the platform. It is relatively easy to evaluate the RTP chamber's leakage by the pressure decay, where the system is charged with the air, closed, and the decay of pressure is measured by the time period. We conducted the determination of a vaporized H₂O₂ of a sufficient concentration to complete decontamination. The performance of the RTP chamber will improve safety and can be completely tested at an ISO Class 5 environment.

  14. Validation of Contamination Control in Rapid Transfer Port Chambers for Pharmaceutical Manufacturing Processes

    Directory of Open Access Journals (Sweden)

    Shih-Cheng Hu

    2016-11-01

    Full Text Available There is worldwide concern with regard to the adverse effects of drug usage. However, contaminants can gain entry into a drug manufacturing process stream from several sources such as personnel, poor facility design, incoming ventilation air, machinery and other equipment for production, etc. In this validation study, we aimed to determine the impact and evaluate the contamination control in the preparation areas of the rapid transfer port (RTP chamber during the pharmaceutical manufacturing processes. The RTP chamber is normally tested for airflow velocity, particle counts, pressure decay of leakage, and sterility. The air flow balance of the RTP chamber is affected by the airflow quantity and the height above the platform. It is relatively easy to evaluate the RTP chamber′s leakage by the pressure decay, where the system is charged with the air, closed, and the decay of pressure is measured by the time period. We conducted the determination of a vaporized H2O2 of a sufficient concentration to complete decontamination. The performance of the RTP chamber will improve safety and can be completely tested at an ISO Class 5 environment.

  15. Definition and determination of the triplet-triplet energy transfer reaction coordinate

    Energy Technology Data Exchange (ETDEWEB)

    Zapata, Felipe; Marazzi, Marco; Castaño, Obis; Frutos, Luis Manuel, E-mail: luisma.frutos@uah.es [Departamento de Química Física, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid (Spain); Acuña, A. Ulises [Instituto de Química Física “Rocasolano”, C.S.I.C., Serrano 119, 28006 Madrid (Spain)

    2014-01-21

    A definition of the triplet-triplet energy transfer reaction coordinate within the very weak electronic coupling limit is proposed, and a novel theoretical formalism is developed for its quantitative determination in terms of internal coordinates The present formalism permits (i) the separation of donor and acceptor contributions to the reaction coordinate, (ii) the identification of the intrinsic role of donor and acceptor in the triplet energy transfer process, and (iii) the quantification of the effect of every internal coordinate on the transfer process. This formalism is general and can be applied to classical as well as to nonvertical triplet energy transfer processes. The utility of the novel formalism is demonstrated here by its application to the paradigm of nonvertical triplet-triplet energy transfer involving cis-stilbene as acceptor molecule. In this way the effect of each internal molecular coordinate in promoting the transfer rate, from triplet donors in the low and high-energy limit, could be analyzed in detail.

  16. Definition and determination of the triplet-triplet energy transfer reaction coordinate

    Science.gov (United States)

    Zapata, Felipe; Marazzi, Marco; Castaño, Obis; Acuña, A. Ulises; Frutos, Luis Manuel

    2014-01-01

    A definition of the triplet-triplet energy transfer reaction coordinate within the very weak electronic coupling limit is proposed, and a novel theoretical formalism is developed for its quantitative determination in terms of internal coordinates The present formalism permits (i) the separation of donor and acceptor contributions to the reaction coordinate, (ii) the identification of the intrinsic role of donor and acceptor in the triplet energy transfer process, and (iii) the quantification of the effect of every internal coordinate on the transfer process. This formalism is general and can be applied to classical as well as to nonvertical triplet energy transfer processes. The utility of the novel formalism is demonstrated here by its application to the paradigm of nonvertical triplet-triplet energy transfer involving cis-stilbene as acceptor molecule. In this way the effect of each internal molecular coordinate in promoting the transfer rate, from triplet donors in the low and high-energy limit, could be analyzed in detail.

  17. Interaction mechanism for energy transfer from Ce to Tb ions in silica

    Energy Technology Data Exchange (ETDEWEB)

    Seed Ahmed, H.A.A. [Department of Physics, University of the Free State, Bloemfontein (South Africa); Department of Physics, University of Khartoum, Khartoum (Sudan); Chae, W.S. [Korea Basic Science Institute (KBSI), Gangneung (Korea, Republic of); Ntwaeaborwa, O.M. [Department of Physics, University of the Free State, Bloemfontein (South Africa); Kroon, R.E., E-mail: KroonRE@ufs.ac.za [Department of Physics, University of the Free State, Bloemfontein (South Africa)

    2016-01-01

    Energy transfer phenomena can play an important role in the development of luminescent materials. In this study, numerical simulations based on theoretical models of non-radiative energy transfer are compared to experimental results for Ce, Tb co-doped silica. Energy transfer from the donor (Ce) to the acceptor (Tb) resulted in a decrease in the Ce luminescence intensity and lifetime. The decrease in intensity corresponded best with the energy transfer models based on the exchange interaction and the dipole-dipole interaction. The critical transfer distance obtained from the fitting using both these models is around 2 nm. Since the exchange interaction requires a distance shorter than 1 nm to occur, the mechanism most likely to account for the energy transfer is concluded to be the dipole–dipole interaction. This is supported by an analysis of the lifetime data.

  18. Rapid transfer of photosynthetic carbon through the plant-soil system in differently managed species-rich grasslands

    NARCIS (Netherlands)

    Deyn, de G.B.; Quirk, H.; Oakley, S.; Ostle, N.J.; Bartgett, R.D.

    2011-01-01

    Plant-soil interactions are central to short-term carbon (C) cycling through the rapid transfer of recently assimilated C from plant roots to soil biota. In grassland ecosystems, changes in C cycling are likely to be influenced by land use and management that changes vegetation and the associated

  19. Single-collision studies of energy transfer and chemical reaction

    Energy Technology Data Exchange (ETDEWEB)

    Valentini, J.J. [Columbia Univ., New York, NY (United States)

    1993-12-01

    The research focus in this group is state-to-state dynamics of reaction and energy transfer in collisions of free radicals such as H, OH, and CH{sub 3} with H{sub 2}, alkanes, alcohols and other hydrogen-containing molecules. The motivation for the work is the desire to provide a detailed understanding of the chemical dynamics of prototype reactions that are important in the production and utilization of energy sources, most importantly in combustion. The work is primarily experimental, but with an important and growing theoretical/computational component. The focus of this research program is now on reactions in which at least one of the reactants and one of the products is polyatomic. The objective is to determine how the high dimensionality of the reactants and products differentiates such reactions from atom + diatom reactions of the same kinematics and energetics. The experiments use highly time-resolved laser spectroscopic methods to prepare reactant states and analyze the states of the products on a single-collision time scale. The primary spectroscopic tool for product state analysis is coherent anti-Stokes Raman scattering (CARS) spectroscopy. CARS is used because of its generality and because the extraction of quantum state populations from CARS spectra is straightforward. The combination of the generality and easy analysis of CARS makes possible absolute cross section measurements (both state-to-state and total), a particularly valuable capability for characterizing reactive and inelastic collisions. Reactant free radicals are produced by laser photolysis of appropriate precursors. For reactant vibrational excitation stimulated Raman techniques are being developed and implemented.

  20. Ion Transfer Battery: Storing Energy by Transferring Ions across Liquid-Liquid Interfaces

    OpenAIRE

    Peljo, Pekka Eero; Bichon, Marie; Girault, Hubert

    2016-01-01

    A battery utilizing the Galvani potential difference between aqueous and organic phases is demonstrated. The battery consists of two organic redox electrolytes separated by an immiscible aqueous phase. The charge is stored by transferring a salt from the aqueous phase into organic phases in ion transfer coupled electron transfer reactions.

  1. GLIMPSE: a rapid decision framework for energy and environmental policy

    Science.gov (United States)

    Over the coming decades, new energy production technologies and the policies that oversee them will affect human health, the vitality of our ecosystems, and the stability of the global climate. The GLIMPSE decision model framework provides insights about the implications of techn...

  2. 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.

  3. 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.

  4. Synthetic system mimicking the energy transfer and charge separation of natural photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Gust, D.; Moore, T.A.

    1985-05-01

    A synthetic molecular triad consisting of a porphyrin P linked to both a quinone Q and a carotenoid polyene C has been prepared as a mimic of natural photosynthesis for solar energy conversion purposes. Laser flash excitation of the porphyrin moiety yields a charge-separated state Csup(+.)-P-Qsup(-.) within 100 ps with a quantum yield of more than 0.25. This charge-separated state has a lifetime on the microsecond time scale in suitable solvents. The triad also models photosynthetic antenna function and photoprotection from singlet oxygen damge. The successful biomimicry of photosynthetic charge separation is in part the result of multistep electron transfers which rapidly separate the charges and leave the system at high potential, but with a considerable barrier to recombination.

  5. Efficient near-field wireless energy transfer using adiabatic system variations

    Energy Technology Data Exchange (ETDEWEB)

    Hamam, Rafif E.; Karalis, Aristeidis; Joannopoulos, John D.; Soljacic, Marin

    2017-11-28

    Disclosed is a method for transferring energy wirelessly including transferring energy wirelessly from a first resonator structure to an intermediate resonator structure, wherein the coupling rate between the first resonator structure and the intermediate resonator structure is .kappa..sub.1B, transferring energy wirelessly from the intermediate resonator structure to a second resonator structure, wherein the coupling rate between the intermediate resonator structure and the second resonator structure is .kappa..sub.B2, and during the wireless energy transfers, adjusting at least one of the coupling rates .kappa..sub.1B and .kappa..sub.B2 to reduce energy accumulation in the intermediate resonator structure and improve wireless energy transfer from the first resonator structure to the second resonator structure through the intermediate resonator structure.

  6. 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.

  7. Tunable negligible-loss energy transfer between dipolar-coupled magnetic disks by stimulated vortex gyration

    OpenAIRE

    Hyunsung Jung; Ki-Suk Lee; Dae-Eun Jeong; Youn-Seok Choi; Young-Sang Yu; Dong-Soo Han; Andreas Vogel; Lars Bocklage; Guido Meier; Mi-Young Im; Peter Fischer; Sang-Koog Kim

    2011-01-01

    A wide variety of coupled harmonic oscillators exist in nature. Coupling between different oscillators allows for the possibility of mutual energy transfer between them and the information-signal propagation. Low-energy input signals and their transport with negligible energy loss are the key technological factors in the design of information-signal processing devices. Here, utilizing the concept of coupled oscillators, we experimentally demonstrated a robust new mechanism for energy transfer...

  8. Tunable energy transfer between dipolar-coupled magnetic disks by stimulated vortex gyration

    OpenAIRE

    Jung, Hyunsung; Lee, Ki-Suk; Jeong, Dae-Eun; Choi, Youn-Seok; Yu, Young-Sang; Han, Dong-Soo; Vogel, Andreas; Bocklage, Lars; Meier, Guido; Im, Mi-Young; Fischer, Peter; Kim, Sang-Koog

    2010-01-01

    A wide variety of coupled harmonic oscillators exist in nature1. Coupling between different oscillators allows for the possibility of mutual energy transfer between them2-4 and the information-signal propagation5,6. Low-energy input signals and their transport with low-energy dissipation are the key technical factors in the design of information processing devices7. Here, utilizing the concept of coupled oscillators, we experimentally demonstrated a robust new mechanism for energy transfer be...

  9. Travelling energy systems: knowledge transfer for energy efficiency and conservation from European to Australian building projects

    Energy Technology Data Exchange (ETDEWEB)

    Glad, Wiktoria (Tema Technology and Social Change, Linkoeping Univ. (Sweden); Inst. for Sustainable Futures, Univ. of Technology, Sydney (Australia))

    2009-07-01

    Energy efficiency and conservation in the Australian built environment have not yet been implemented to any great extent. Despite favourable prerequisites, such as vast windswept unpopulated areas suitable for wind power and many hours of direct sunlight in most populated areas, electricity is mainly generated by burning brown coal and buildings are poorly equipped for hot summers and cool winters. Australia urgently needs to convert to alternative energy sources and implement energy efficiency measures, since its carbon dioxide emissions per capita are among the highest in the world. In a recent major redevelopment in Sydney, the Carlton and United Brewery (CUB) site knowledge of energy efficiency and conservation measures used in European buildings was transferred and implemented in local designs and infrastructure. This knowledge came mainly from urban planning and developments in London, but also from high-profile architectural firms based in Paris and Germany. The arrival of this knowledge in Australia led to phases when the knowledge was translated and enacted in local spaces and the constituent ideas were transformed into action. The present research is based on ten months of ethnographic fieldwork in which the planning and design of the CUB site was observed. The results of the study identify barriers to and opportunities for energy system knowledge transfer between different cultures and local spaces. Substantial time must be spent overcoming cultural barriers, so the involved parties can start talking the same language. This is not only true for stakeholders operating in different continents, but for stakeholders operating in different local arenas in the same country.

  10. Imaging and Manipulating Energy Transfer Among Quantum Dots at Individual Dot Resolution.

    Science.gov (United States)

    Nguyen, Duc; Nguyen, Huy A; Lyding, Joseph W; Gruebele, Martin

    2017-06-27

    Many processes of interest in quantum dots involve charge or energy transfer from one dot to another. Energy transfer in films of quantum dots as well as between linked quantum dots has been demonstrated by luminescence shift, and the ultrafast time-dependence of energy transfer processes has been resolved. Bandgap variation among dots (energy disorder) and dot separation are known to play an important role in how energy diffuses. Thus, it would be very useful if energy transfer could be visualized directly on a dot-by-dot basis among small clusters or within films of quantum dots. To that effect, we report single molecule optical absorption detected by scanning tunneling microscopy (SMA-STM) to image energy pooling from donor into acceptor dots on a dot-by-dot basis. We show that we can manipulate groups of quantum dots by pruning away the dominant acceptor dot, and switching the energy transfer path to a different acceptor dot. Our experimental data agrees well with a simple Monte Carlo lattice model of energy transfer, similar to models in the literature, in which excitation energy is transferred preferentially from dots with a larger bandgap to dots with a smaller bandgap.

  11. On Current Conversion between Particle Rapidity and Pseudorapidity Distributions in High Energy Collisions

    Directory of Open Access Journals (Sweden)

    Fu-Hu Liu

    2013-01-01

    Full Text Available In high energy collisions, one usually needs to give a conversion between the particle rapidity and pseudorapidity distributions. Currently, two equivalent conversion formulas are used in experimental and theoretical analyses. An investigation in the present work shows that the two conversions are incomplete. Then, we give a revision on the current conversion between the particle rapidity and pseudorapidity distributions.

  12. The 2H(e, e' p)n reaction at large energy transfers

    NARCIS (Netherlands)

    Willering, Hendrik Willem

    2003-01-01

    At the ELSA accelerator facillity in Bonn, Germany, we have measured the deutron "breakup" reaction 2H(e,e' p)n at four-momentum transfers around Q2 = -0 .20(GeV/c)2 with an electron beam energy of E0 = 1.6 GeV. The cross section has been determined for energy transfers extending from the

  13. Momentum and Energy Transfer in an Ionospheric Critical Ionization Velocity Experiment

    OpenAIRE

    Bolin, O.; Brenning, N.; Swenson, C. M.; Primdahl, Fritz

    1995-01-01

    We present new data from the subpayload of the GRIT II ionospheric active injection experiment. The analysis made possible by these data provides a good understanding of the momentum transfer between the injected ions and the ambient ionosphere. It resolves the conflict between the two competing models for the energy transfer from the newly created ions to hot electrons, while also giving a natural coupling between the energy and momentum transfer processes.

  14. Mutations to R. sphaeroides Reaction Center Perturb Energy Levels and Vibronic Coupling but Not Observed Energy Transfer Rates.

    Science.gov (United States)

    Flanagan, Moira L; Long, Phillip D; Dahlberg, Peter D; Rolczynski, Brian S; Massey, Sara C; Engel, Gregory S

    2016-03-10

    The bacterial reaction center is capable of both efficiently collecting and quickly transferring energy within the complex; therefore, the reaction center serves as a convenient model for both energy transfer and charge separation. To spectroscopically probe the interactions between the electronic excited states on the chromophores and their intricate relationship with vibrational motions in their environment, we examine coherences between the excited states. Here, we investigate this question by introducing a series of point mutations within 12 Å of the special pair of bacteriochlorophylls in the Rhodobacter sphaeroides reaction center. Using two-dimensional spectroscopy, we find that the time scales of energy transfer dynamics remain unperturbed by these mutations. However, within these spectra, we detect changes in the mixed vibrational-electronic coherences in these reaction centers. Our results indicate that resonance between bacteriochlorophyll vibrational modes and excitonic energy gaps promote electronic coherences and support current vibronic models of photosynthetic energy transfer.

  15. Communication: Broad manifold of excitonic states in light-harvesting complex 1 promotes efficient unidirectional energy transfer in vivo

    Science.gov (United States)

    Sohail, Sara H.; Dahlberg, Peter D.; Allodi, Marco A.; Massey, Sara C.; Ting, Po-Chieh; Martin, Elizabeth C.; Hunter, C. Neil; Engel, Gregory S.

    2017-10-01

    In photosynthetic organisms, the pigment-protein complexes that comprise the light-harvesting antenna exhibit complex electronic structures and ultrafast dynamics due to the coupling among the chromophores. Here, we present absorptive two-dimensional (2D) electronic spectra from living cultures of the purple bacterium, Rhodobacter sphaeroides, acquired using gradient assisted photon echo spectroscopy. Diagonal slices through the 2D lineshape of the LH1 stimulated emission/ground state bleach feature reveal a resolvable higher energy population within the B875 manifold. The waiting time evolution of diagonal, horizontal, and vertical slices through the 2D lineshape shows a sub-100 fs intra-complex relaxation as this higher energy population red shifts. The absorption (855 nm) of this higher lying sub-population of B875 before it has red shifted optimizes spectral overlap between the LH1 B875 band and the B850 band of LH2. Access to an energetically broad distribution of excitonic states within B875 offers a mechanism for efficient energy transfer from LH2 to LH1 during photosynthesis while limiting back transfer. Two-dimensional lineshapes reveal a rapid decay in the ground-state bleach/stimulated emission of B875. This signal, identified as a decrease in the dipole strength of a strong transition in LH1 on the red side of the B875 band, is assigned to the rapid localization of an initially delocalized exciton state, a dephasing process that frustrates back transfer from LH1 to LH2.

  16. Rotational Energy Transfer of N2 Determined Using a New Ab Initio Potential Energy Surface

    Science.gov (United States)

    Huo, Winifred M.; Stallcop, James R.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    A new N2-N2 rigid-rotor surface has been determined using extensive Ab Initio quantum chemistry calculations together with recent experimental data for the second virial coefficient. Rotational energy transfer is studied using the new potential energy surface (PES) employing the close coupling method below 200 cm(exp -1) and coupled state approximation above that. Comparing with a previous calculation based on the PES of van der Avoird et al.,3 it is found that the new PES generally gives larger cross sections for large (delta)J transitions, but for small (delta)J transitions the cross sections are either comparable or smaller. Correlation between the differences in the cross sections and the two PES will be attempted. The computed cross sections will also be compared with available experimental data.

  17. Description of High-Energy pp Collisions Using Tsallis Thermodynamics: Transverse Momentum and Rapidity Distributions

    CERN Document Server

    Marques, L.; Deppman, A.

    2015-01-01

    A systematic analysis of transverse momentum and rapidity distributions measured in high-energy proton - proton (pp) collisions for energies ranging from 53 GeV to 7 TeV using Tsallis thermodynamics is presented. The excellent description of all transverse momentum spectra obtained in earlier analyses is confirmed and extended. All energies can be described by a single Tsallis temperature of 68 +/- 5 MeV at all beam energies and particle types investigated (43 in total). The value of the entropic index, q, shows a wider spread but is always close to q approx 1.146. These values are then used to describe the rapidity distributions using a superposition of two Tsallis fireballs along the rapidity axis. It is concluded that the hadronic system created in high-energy p - p collisions between 53 GeV and 7 TeV can be seen as obeying Tsallis thermodynamics.

  18. Energy transfers in large-scale and small-scale dynamos

    Science.gov (United States)

    Samtaney, Ravi; Kumar, Rohit; Verma, Mahendra

    2015-11-01

    We present the energy transfers, mainly energy fluxes and shell-to-shell energy transfers in small-scale dynamo (SSD) and large-scale dynamo (LSD) using numerical simulations of MHD turbulence for Pm = 20 (SSD) and for Pm = 0.2 on 10243 grid. For SSD, we demonstrate that the magnetic energy growth is caused by nonlocal energy transfers from the large-scale or forcing-scale velocity field to small-scale magnetic field. The peak of these energy transfers move towards lower wavenumbers as dynamo evolves, which is the reason for the growth of the magnetic fields at the large scales. The energy transfers U2U (velocity to velocity) and B2B (magnetic to magnetic) are forward and local. For LSD, we show that the magnetic energy growth takes place via energy transfers from large-scale velocity field to large-scale magnetic field. We observe forward U2U and B2B energy flux, similar to SSD.

  19. Quantum Coherence as a Witness of Vibronically Hot Energy Transfer in Bacterial Reaction Centre

    CERN Document Server

    Paleček, David; Westenhoff, Sebastian; Zigmantas, Donatas

    2016-01-01

    Photosynthetic proteins have evolved over billions of years so as to undergo optimal energy transfer to the sites of charge separation. Based on spectroscopically detected quantum coherences, it has been suggested that this energy transfer is partially wavelike. This conclusion critically depends on assignment of the coherences to the evolution of excitonic superpositions. Here we demonstrate for a bacterial reaction centre protein that long-lived coherent spectroscopic oscillations, which bear canonical signatures of excitonic superpositions, are essentially vibrational excited state coherences shifted to the ground state of the chromophores . We show that appearance of these coherences is brought about by release of electronic energy during the energy transfer. Our results establish how energy migrates on vibrationally hot chromophores in the reaction centre and they call for a re-examination of claims of quantum energy transfer in photosynthesis.

  20. 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.

  1. Electronic energy transfer in tetracene-doped p-terphenyl nanoparticles: Extraordinarily high fluorescence enhancement and quenching efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Mitsui, Masaaki, E-mail: smmitsu@ipc.shizuoka.ac.jp; Kawano, Yuya

    2013-06-20

    Highlights: ► Tc/pTP-NPs at various doping ratios are produced by reprecipitation in water. ► The energy transfer in Tc/pTP-NPs is investigated. ► More than 10{sup 4}pTP donors were quenched by a single Tc acceptor. ► Efficient energy transfer is attributed to the rapid exciton diffusion in the NPs. - Abstract: A series of tetracene (Tc)-doped p-terphenyl (pTP) nanoparticles (Tc/pTP-NPs) were produced at various doping ratios by reprecipitation in water. The Tc/pTP-NPs are disk-like with a mean diameter of 75 nm and height of 7 nm, which were determined by scanning electron microscopy and atomic force microscopy, and exhibited electronic delocalization through H-type aggregation of the pTP molecules. Electronic energy transfer in the Tc/pTP-NPs was examined using steady-state and time-resolved fluorescence spectroscopy and fluorescence anisotropy experiments: pTP-NPs serve as an excellent light-harvesting nano-matrix with a large absorption coefficient that exceeds 10{sup 9} M{sup −1} cm{sup −1}. Furthermore, Stern–Volmer analysis of the donor emission was performed by changing the dopant concentration; this showed that a single Tc acceptor quenched more than 10{sup 4}pTP donors. Comparison of the experimental and theoretical energy transfer efficiencies indicated that the efficient energy transfer can be attributed to two-dimensional exciton diffusion in the host nanoparticles.

  2. Linear energy transfer incorporated intensity modulated proton therapy optimization

    Science.gov (United States)

    Cao, Wenhua; Khabazian, Azin; Yepes, Pablo P.; Lim, Gino; Poenisch, Falk; Grosshans, David R.; Mohan, Radhe

    2018-01-01

    The purpose of this study was to investigate the feasibility of incorporating linear energy transfer (LET) into the optimization of intensity modulated proton therapy (IMPT) plans. Because increased LET correlates with increased biological effectiveness of protons, high LETs in target volumes and low LETs in critical structures and normal tissues are preferred in an IMPT plan. However, if not explicitly incorporated into the optimization criteria, different IMPT plans may yield similar physical dose distributions but greatly different LET, specifically dose-averaged LET, distributions. Conventionally, the IMPT optimization criteria (or cost function) only includes dose-based objectives in which the relative biological effectiveness (RBE) is assumed to have a constant value of 1.1. In this study, we added LET-based objectives for maximizing LET in target volumes and minimizing LET in critical structures and normal tissues. Due to the fractional programming nature of the resulting model, we used a variable reformulation approach so that the optimization process is computationally equivalent to conventional IMPT optimization. In this study, five brain tumor patients who had been treated with proton therapy at our institution were selected. Two plans were created for each patient based on the proposed LET-incorporated optimization (LETOpt) and the conventional dose-based optimization (DoseOpt). The optimized plans were compared in terms of both dose (assuming a constant RBE of 1.1 as adopted in clinical practice) and LET. Both optimization approaches were able to generate comparable dose distributions. The LET-incorporated optimization achieved not only pronounced reduction of LET values in critical organs, such as brainstem and optic chiasm, but also increased LET in target volumes, compared to the conventional dose-based optimization. However, on occasion, there was a need to tradeoff the acceptability of dose and LET distributions. Our conclusion is that the

  3. Linear energy transfer incorporated intensity modulated proton therapy optimization.

    Science.gov (United States)

    Cao, Wenhua; Khabazian, Azin; Yepes, Pablo P; Lim, Gino J; Poenisch, Falk; Grosshans, David R; Mohan, Radhe

    2017-11-13

    The purpose of this study was to investigate the feasibility of incorporating linear energy transfer (LET) into the optimization of intensity modulated proton therapy (IMPT) plans. Because increased LET correlates with increased biological effectiveness of protons, high LETs in target volumes and low LETs in critical structures and normal tissues are preferred in an IMPT plan. However, if not explicitly incorporated into the optimization criteria, different IMPT plans may yield similar physical dose distributions but greatly different LET, specifically dose-averaged LET, distributions. Conventionally, the IMPT optimization criteria (or cost function) only includes dose-based objectives in which the relative biological effectiveness (RBE) is assumed to have a constant value of 1.1. In this study, we added LET-based objectives for maximizing LET in target volumes and minimizing LET in critical structures and normal tissues. Due to the fractional programming nature of the resulting model, we used a variable reformulation approach so that the optimization process is computationally equivalent to conventional IMPT optimization. In this study, five brain tumor patients who had been treated with proton therapy at our institution were selected. Two plans were created for each patient based on the proposed LET-incorporated optimization (LETOpt) and the conventional dose-based optimization (DoseOpt). The optimized plans were compared in terms of both dose (assuming a constant RBE of 1.1 as adopted in clinical practice) and LET. Both optimization approaches were able to generate comparable dose distributions. The LET-incorporated optimization achieved not only pronounced reduction of LET values in critical organs, such as brainstem and optic chiasm, but also increased LET in the target volumes, compared to the conventional dose-based optimization. However, on occasion, there was a need to tradeoff the acceptability of dose and LET distributions. Our conclusion is that the

  4. 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

  5. Analysis on spatial transfer model of energy development layout and the ecological footprint affection

    Science.gov (United States)

    Wei, Xiaoxia; Zhang, Jinfang

    2017-01-01

    Consider the global energy interconnection, the global is concentrating on carrying out clean energy alternative, which is mainly focusing on using the clean energy to take place of fossil energy, and change the global energy layout and ecological atmosphere condition. This research gives the energy spatial transfer model of energy development layout to analyse the global energy development layout condition and ecological affection. And it is a fast and direct method to analyse its energy usage process and environmental affection. The paper also gives out a system dynamics model of energy spatial transfer shows, which electric power transmission is better than original energy usage and transportation. It also gives the comparison of different parameters. The energy spatial transfer can affect the environment directly. Consider its three environmental factors, including energy saving, climate changing and conventional pollutant emission reduction, synthetic combine with the spatial transfer model, it can get the environmental change parameters, which showed that with the clean energy wide usage, the ecological footprint affection will be affected significantly.

  6. Technology transfer for the US Department of Energy's Energy Storage Program: Volume 2, Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Bruneau, C.L.; Fassbender, L.L.

    1988-10-01

    This document contains the appendices to Technology Transfer Recommendations for the US Department of Energy's Storage Program (PNL-6484, Vol. 1). These appendices are a list of projects, publications, and presentations connected with the Energy Storage (STOR) program. In Volume 1, the technology transfer activities of the STOR program are examined and mechanisms for increasing the effectiveness of those activities are recommended.

  7. Photoinduced energy and electron transfer in rubrene-benzoquinone and rubrene-porphyrin systems

    KAUST Repository

    Khan, Jafar Iqbal

    2014-11-01

    Excited-state electron and energy transfer from singlet excited rubrene (Ru) to benzoquinone (BQ) and tetra-(4-aminophenyl) porphyrin (TAPP) were investigated by steady-state absorption and emission, time-resolved transient absorption, and femtosecond (fs)-nanosecond (ns) fluorescence spectroscopy. The low reduction potential of BQ provides the high probability of electron transfer from the excited Ru to BQ. Steady-state and time-resolved results confirm such an excited electron transfer scenario. On the other hand, strong spectral overlap between the emission of Ru and absorption of TAPP suggests that energy transfer is a possible deactivation pathway of the Ru excited state.

  8. Real-space investigation of energy transfer in heterogeneous molecular dimers

    Science.gov (United States)

    Imada, Hiroshi; Miwa, Kuniyuki; Imai-Imada, Miyabi; Kawahara, Shota; Kimura, Kensuke; Kim, Yousoo

    2016-10-01

    Given its central role in photosynthesis and artificial energy-harvesting devices, energy transfer has been widely studied using optical spectroscopy to monitor excitation dynamics and probe the molecular-level control of energy transfer between coupled molecules. However, the spatial resolution of conventional optical spectroscopy is limited to a few hundred nanometres and thus cannot reveal the nanoscale spatial features associated with such processes. In contrast, scanning tunnelling luminescence spectroscopy has revealed the energy dynamics associated with phenomena ranging from single-molecule electroluminescence, absorption of localized plasmons and quantum interference effects to energy delocalization and intervalley electron scattering with submolecular spatial resolution in real space. Here we apply this technique to individual molecular dimers that comprise a magnesium phthalocyanine and a free-base phthalocyanine (MgPc and H2Pc) and find that locally exciting MgPc with the tunnelling current of the scanning tunnelling microscope generates a luminescence signal from a nearby H2Pc molecule as a result of resonance energy transfer from the former to the latter. A reciprocating resonance energy transfer is observed when exciting the second singlet state (S2) of H2Pc, which results in energy transfer to the first singlet state (S1) of MgPc and final funnelling to the S1 state of H2Pc. We also show that tautomerization of H2Pc changes the energy transfer characteristics within the dimer system, which essentially makes H2Pc a single-molecule energy transfer valve device that manifests itself by blinking resonance energy transfer behaviour.

  9. Rapidity dependence of charged pion production at relativistic energies using Tsallis statistics

    Energy Technology Data Exchange (ETDEWEB)

    Ristea, Oana; Jipa, Alexandru [University of Bucharest, Faculty of Physics, Bucharest - Magurele (Romania); Ristea, Catalin [University of Bucharest, Faculty of Physics, Bucharest - Magurele (Romania); Institute of Space Science, Bucharest - Magurele (Romania)

    2017-05-15

    Transverse momentum distributions of charged pions produced in Au+Au collisions at 62.4 GeV, 130 GeV, 200 GeV, Cu+Cu and d+Au collisions at 200 GeV, p+p collisions at 62.4 and 200 GeV and Pb+Pb collisions at 17.3 GeV are studied using the Tsallis distribution as a parametrization. The non-extensivity parameter and Tsallis volume increase with energy, while the Tsallis temperature shows a decrease at higher energies. Using BRAHMS p{sub T} spectra obtained in Au+Au collisions at 62.4 GeV and 200 GeV, Tsallis fit parameters are obtained on a very wide rapidity range. Results are compared with p+p and Cu+Cu data and changes of Tsallis parameters with rapidity and energy are investigated. We found that non-extensivity parameter q shows a decrease from midrapidity to forward rapidities for all the studied systems. Tsallis volume, V, increases with the system size from p+p, Cu+Cu to Au+Au, both in central rapidity region and at forward rapidities. The values of temperatures increase with rapidity, but the T/cosh(y) ratio is constant as a function of rapidity. (orig.)

  10. Chirality and energy transfer amplified circularly polarized luminescence in composite nanohelix

    Science.gov (United States)

    Yang, Dong; Duan, Pengfei; Zhang, Li; Liu, Minghua

    2017-06-01

    Transfer of both chirality and energy information plays an important role in biological systems. Here we show a chiral donor π-gelator and assembled it with an achiral π-acceptor to see how chirality and energy can be transferred in a composite donor-acceptor system. It is found that the individual chiral gelator can self-assemble into nanohelix. In the presence of the achiral acceptor, the self-assembly can also proceed and lead to the formation of the composite nanohelix. In the composite nanohelix, an energy transfer is realized. Interestingly, in the composite nanohelix, the achiral acceptor can both capture the supramolecular chirality and collect the circularly polarized energy from the chiral donor, showing both supramolecular chirality and energy transfer amplified circularly polarized luminescence (ETACPL).

  11. 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.

  12. Peculiarities in the energy transfer by waves on strained strings

    Science.gov (United States)

    Butikov, Eugene I.

    2013-12-01

    Localization of elastic potential energy associated with waves in a stretched string is discussed. The influence of nonlinear coupling between transverse and longitudinal waves on the density of energy is investigated by considering the examples of stationary traveling and standing waves. Misunderstandings about different expressions for the density of potential energy encountered in the literature are clarified. The common statement regarding the relationship between the densities of kinetic and potential energies in a transverse wave is criticized.

  13. 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.

  14. Effects of Herzberg-Teller vibronic coupling on coherent excitation energy transfer

    Science.gov (United States)

    Zhang, Hou-Dao; Qiao, Qin; Xu, Rui-Xue; Yan, YiJing

    2016-11-01

    In this work, we study the effects of non-Condon vibronic coupling on the quantum coherence of excitation energy transfer, via the exact dissipaton-equation-of-motion evaluations on excitonic model systems. Field-triggered excitation energy transfer dynamics and two dimensional coherent spectroscopy are simulated for both Condon and non-Condon vibronic couplings. Our results clearly demonstrate that the non-Condon vibronic coupling intensifies the dynamical electronic-vibrational energy transfer and enhances the total system-and-bath quantum coherence. Moreover, the hybrid bath dynamics for non-Condon effects enriches the theoretical calculation, and further sheds light on the interpretation of the experimental nonlinear spectroscopy.

  15. Thickness and local field effects on energy transfer rate in coupled quantum wells system: Linear regime

    Energy Technology Data Exchange (ETDEWEB)

    Vazifehshenas, T.; Bahrami, B. [Department of Physics, Shahid Beheshti University, G.C., Evin, 1983963113 Tehran (Iran, Islamic Republic of); Salavati-fard, T., E-mail: taha@udel.edu [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States)

    2012-12-15

    We investigate theoretically the dependence of energy transfer rate in Double-Quantum-Well system on the well thickness by using the balance equation formalism. Also, by including the local field correction in our calculations through the zero- and finite-temperature Hubbard approximations, we study the effect of the short-range interactions on the energy transfer phenomenon. Calculations consider both the static and dynamic screening approximations. Our numerical results predict that the energy transfer rate increases considerably by increasing the layers' thicknesses and by taking into account the short-range interactions, as well.

  16. Energy Transfer Process of Eu3+ Ions Doped in Tellurite Glass

    Science.gov (United States)

    Hong, Tran Thi; Dung, Phan Tien; Quang, Vu Xuan

    2016-05-01

    Tellurite glass doped with different concentrations of Eu3+ ions has been prepared by the conventional melting process. Photoluminescence, Raman spectra, phonon side-band spectra, and Judd-Ofelt analysis were carried out. Some spectroscopic parameters were estimated to predict the luminescence efficiency of the materials. The energy transfer between the rare-earth ions was observed, and a model for its cross-relaxation was proposed and quantitatively estimated. The charged intrinsic defects in the form of nonbridging oxygen (NBO) were determined, and the energy transfer between NBO and rare-earth ions observed. The energy-transfer-induced Eu3+ photoluminescence enhancement in tellurite glass is studied.

  17. Shape similarity of charge-transfer (CT) excitation energy curves in a series of donor-acceptor complexes and its description with a transferable energy of CT orbital

    Science.gov (United States)

    Gritsenko, O. V.

    2017-08-01

    A simple nature of charge-transfer (CT) in the prototype complexes Dp -F2 (Dp =NH3 , H2O) manifests itself in a very close shape of their CT excitation energy curves ωCT (R) along the donor-acceptor separation R. It affords a simple orbital description in terms of the CT orbitals (CTOs) obtained with a transformation of the virtual orbitals of the standard local density approximation (LDA). The transferable energy of the relevant CTO as a function of R closely approximates the common shape of ωCT (R) , while the height of the individual curve is determined with the ionization potential of Dp .

  18. 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

  19. Construction of energy transfer systems within nanosized polymer micelles and their fluorescence modulation properties.

    Science.gov (United States)

    Chen, Jian; Zeng, Fang; Wu, Shuizhu

    2010-04-06

    The nanoparticle-based fluorescence resonance energy transfer (FRET) systems have recently attracted considerable attention due to some of their advantages; however, these systems are structurally more complicated than that of small molecule systems, and the energy transfer behavior for particle systems has been seldom investigated. In this study, we synthesized a series of ABC triblock copolymers that contain hydrophilic poly(ethylene oxide) (PEO), hydrophobic poly(styrene) (PS) and photochromic poly(2-(3-(3',3'-dimethyl-6-nitrospiro(indoline-2',2-[2H-1]benzopyran)-1'-yl)propanoylo-xy)ethyl methacrylate) (PSPMA) blocks by using the sequential two-step atom transfer radical polymerization (ATRP). The amphiphilic micelles made from these copolymers can incorporate a hydrophobic fluorescent dye, the nitrobenzoxadiazolyl derivative (NBD), thus forming a water dispersible energy transfer system with the fluorescent dye NBD as the donor and spiropyran moieties as the potential acceptor. The spectral properties of NBD/triblock copolymers with varied PS block lengths and PSPMA block lengths have been investigated; the results indicate that the length of PS block in triblock copolymers can affect the energy transfer efficiency of the micelle-based fluorescence modulation system, the micelles with moderate PS block length are preferable for forming FRET system with higher energy transfer efficiency, and short PSPMA blocks (less than 5 repetition units) are enough for efficient energy transfer.

  20. Mechanisms of energy conversion and transfer in bioluminescence. Progress report, August 15, 1976--November 14, 1977. [Renilla (anthozoa)

    Energy Technology Data Exchange (ETDEWEB)

    Cormier, M.J.

    1977-01-01

    Progress is reported on the following studies: isolation of luciferase and green fluorescent protein (GFP) from Renilla; chemical properties and chemical reactions of luciferase and GFP; and analogy of energy transfer in bioluminescence to energy transfer in photosynthesis. (HLW)

  1. Role of cation size in the energy of electron transfer to 1:1 polyoxometalate ion pairs {(M+)(Xn+VW11O40)}(8–n)–(M=Li, Na, K)

    Science.gov (United States)

    Vladimir A. Grigoriev; Craig L. Hill; Ira A. Weinstock

    2000-01-01

    The use of soluble salts of polyoxometalates (d0-early-transition metal oxygen-anion clusters or POMs) as selective oxidation or electron-transfer catalysts, as probes in physical-organic and biological chemistry, and in the study of electron-and energy-transfer phenomena constitutes a substantial and rapidly growing literature. While rarely addressed, however, POM...

  2. Numerical Simulations of the Kinetic Energy Transfer in the Bath of a BOF Converter

    Science.gov (United States)

    Zhou, Xiaobin; Ersson, Mikael; Zhong, Liangcai; Jönsson, Pär

    2016-02-01

    The paper focuses on the fundamental aspects of the kinetic energy transfer from a top and bottom gas injection to the bath of the basic oxygen furnace (BOF) by applying a mathematical model. The analyses revealed that the energy transfer is less efficient when top lance height is lowered or the flowrate is increased in the top blowing operations. However, an inverse trend was found that the kinetic energy transfer is increased when the bottom flowrate is increased for the current bottom blowing operation conditions. The kinetic energy transfer index results indicated that the energy transfer for the bottom blowing is much more efficient than that of the top blowing operations. To understand the effects of the upper buoyant phase on the energy dissipation of the bulk liquid in the bath, different mass and physical properties of slag and foam were considered in the bottom blowing simulations. The slag on top of the bath is found to dissipate by 6.6, 9.4, and 11.2 pct for slag mass values of 5, 9, and 15 t compared to the case without slag atop the surface of the bath, respectively. The results showed that the kinetic energy transfer is not largely influenced by the viscosity of the upper slag or the foaming phases.

  3. A model for energy transfer in collisions of atoms with highly excited molecules.

    Science.gov (United States)

    Houston, Paul L; Conte, Riccardo; Bowman, Joel M

    2015-05-21

    A model for energy transfer in the collision between an atom and a highly excited target molecule has been developed on the basis of classical mechanics and turning point analysis. The predictions of the model have been tested against the results of trajectory calculations for collisions of five different target molecules with argon or helium under a variety of temperatures, collision energies, and initial rotational levels. The model predicts selected moments of the joint probability distribution, P(Jf,ΔE) with an R(2) ≈ 0.90. The calculation is efficient, in most cases taking less than one CPU-hour. The model provides several insights into the energy transfer process. The joint probability distribution is strongly dependent on rotational energy transfer and conservation laws and less dependent on vibrational energy transfer. There are two mechanisms for rotational excitation, one due to motion normal to the intermolecular potential and one due to motion tangential to it and perpendicular to the line of centers. Energy transfer is found to depend strongly on the intermolecular potential and only weakly on the intramolecular potential. Highly efficient collisions are a natural consequence of the energy transfer and arise due to collisions at "sweet spots" in the space of impact parameter and molecular orientation.

  4. Bispectral experimental estimation of the nonlinear energy transfer in two-dimensional plasma turbulence

    DEFF Research Database (Denmark)

    Manz, P.; Ramisch, M.; Stroth, U.

    2008-01-01

    -wave turbulence. The density fluctuations, which at the realistic collisionality are advected as a passive scalar with the vorticity, show power transfer from large to small scales, while the spectral power in potential fluctuations, which represents the energy, is transferred as an inverse cascade to larger...

  5. Ultrafast energy transfer in chlorosomes from the green photosynthetic bacterium Chloroflexus aurantiacus

    Energy Technology Data Exchange (ETDEWEB)

    Savikhin, S.; Struve, W.S. [Ames Lab., IA (United States)]|[Iowa State Univ., Ames, IA (United States); Zhu, Y.; Blankenship, R.E. [Arizona State Univ., Tempe, AZ (United States)

    1996-02-29

    Energy transfers between the bacteriochlorophyll c and a antennae in light-harvesting chlorosomes from the green bacterium Chloroflexus aurantiacus have been studied in two-color pump-probe experiments with improved sensitivity and wavelength versatility. The BChl c {yields} BChl a energy transfers are well simulated with biexponential kinetics, with lifetimes of 2-3 and 11 ps. They do not exhibit an appreciable subpicosecond component. In the context of a kinetic model for chlorosomes, these lifetimes suggest that both internal BChl c processes and the BChl c {yields} BChl a energy-transfer step contribute materially to the empirical rod-to-baseplate energy-transfer kinetics. 11 refs., 2 figs., 1 tab.

  6. Local Measurement of Fuel Energy Deposition and Heat Transfer Environment During Fuel Lifetime Using Controlled Calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Don W. Miller; Andrew Kauffmann; Eric Kreidler; Dongxu Li; Hanying Liu; Daniel Mills; Thomas D. Radcliff; Joseph Talnagi

    2001-12-31

    A comprehensive description of the accomplishments of the DOE grant titled, ''Local Measurement of Fuel Energy Deposition and Heat Transfer Environment During Fuel Lifetime using Controlled Calorimetry''.

  7. Energy Link Optimization in a Wireless Power Transfer Grid under Energy Autonomy Based on the Improved Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Zhihao Zhao

    2016-08-01

    Full Text Available In this paper, an optimization method is proposed for the energy link in a wireless power transfer grid, which is a regional smart microgrid comprised of distributed devices equipped with wireless power transfer technology in a certain area. The relevant optimization model of the energy link is established by considering the wireless power transfer characteristics and the grid characteristics brought in by the device repeaters. Then, a concentration adaptive genetic algorithm (CAGA is proposed to optimize the energy link. The algorithm avoided the unification trend by introducing the concentration mechanism and a new crossover method named forward order crossover, as well as the adaptive parameter mechanism, which are utilized together to keep the diversity of the optimization solution groups. The results show that CAGA is feasible and competitive for the energy link optimization in different situations. This proposed algorithm performs better than its counterparts in the global convergence ability and the algorithm robustness.

  8. Effect of energy transfer from atomic electron shell to an α particle emitted by decaying nucleus

    Energy Technology Data Exchange (ETDEWEB)

    Igashov, S. Yu., E-mail: igashov@theor.mephi.ru [All-Russian Research Institute of Automatics (Russian Federation); Tchuvil’sky, Yu. M. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

    2016-12-15

    The process of energy transfer from the electron shell of an atom to an α particle propagating through the shell is formulated mathematically. Using the decay of the {sup 226}Ra nucleus as an example, it is demonstrated that this phenomenon increases the α-decay intensity in contrast with other known effects of similar type. Moreover, the α decay of the nucleus is more strongly affected by the energy transfer than by all other effects taken together.

  9. Intra/Inter-Particle Energy Transfer of Luminescence Nanocrystals for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Ching-Ping Liu

    2012-01-01

    Full Text Available Elaborate design of energy transfer systems in luminescent nanocrystals revealed tremendous advantages in nanotechnology, especially in biosensing and drug delivery systems. Recently, upconversion nanoparticles have been discussed as promising probes as labels in biological assays and imaging. This article reviews the works performed in the recent years using quantum dot- and rare-earth doped nanoparticle-based energy transfer systems for biomedical applications.

  10. Elucidating energy and electron transfer dynamics within molecular assemblies for solar energy conversion

    Science.gov (United States)

    Morseth, Zachary Aaron

    The use of sunlight to make chemical fuels (i.e. solar fuels) is an attractive approach in the quest to develop sustainable energy sources. Using nature as a guide, assemblies for artificial photosynthesis will need to perform multiple functions. They will need to be able to harvest light across a broad region of the solar spectrum, transport excited-state energy to charge-separation sites, and then transport and store redox equivalents for use in the catalytic reactions that produce chemical fuels. This multifunctional behavior will require the assimilation of multiple components into a single macromolecular system. A wide variety of different architectures including porphyrin arrays, peptides, dendrimers, and polymers have been explored, with each design posing unique challenges. Polymer assemblies are attractive due to their relative ease of production and facile synthetic modification. However, their disordered nature gives rise to stochastic dynamics not present in more ordered assemblies. The rational design of assemblies requires a detailed understanding of the energy and electron transfer events that follow light absorption, which can occur on timescales ranging from femtoseconds to hundreds of microseconds, necessitating the use of sophisticated techniques. We have used a combination of time-resolved absorption and emission spectroscopies with observation times that span nine orders of magnitude to follow the excited-state evolution within single-site and polymer-based molecular assemblies. We complement experimental observations with electronic structure calculations, molecular dynamics simulations, and kinetic modeling to develop a microscopic view of these dynamics. This thesis provides an overview of work on single-site molecular assemblies and polymers decorated with pendant chromophores, both in solution and on surfaces. This work was made possible through extensive collaboration with Dr. Kirk Schanze's and Dr. John Reynolds' research groups who

  11. A Microelectromechanical High-Density Energy Storage/Rapid Release System

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, M. Steven; Allen, Jim J.; Meeks, Kent D.; Jensen, Brian D.; Miller, Sam L.

    1999-07-21

    One highly desirable characteristic of electrostatically driven microelectromechanical systems (MEMS) is that they consume very little power. The corresponding drawback is that the force they produce may be inadequate for many applications. It has previously been demonstrated that gear reduction units or microtransmissions can substantially increase the torque generated by microengines. Operating speed, however, is also reduced by the transmission gear ratio. Some applications require both high speed and high force. If this output is only required for a limited period of time, then energy could be stored in a mechanical system and rapidly released upon demand. We have designed, fabricated, and demonstrated a high-density energy storage/rapid release system that accomplishes this task. Built using a 5-level surface micromachining technology, the assembly closely resembles a medieval crossbow. Energy releases on the order of tens of nanojoules have already been demonstrated, and significantly higher energy systems are under development.

  12. Non-contact pumping of light emitters via non-radiative energy transfer

    Science.gov (United States)

    Klimov, Victor I.; Achermann, Marc

    2010-01-05

    A light emitting device is disclosed including a primary light source having a defined emission photon energy output, and, a light emitting material situated near to said primary light source, said light emitting material having an absorption onset equal to or less in photon energy than the emission photon energy output of the primary light source whereby non-radiative energy transfer from said primary light source to said light emitting material can occur yielding light emission from said light emitting material.

  13. Numerical simulations of energy transfer in two collisionless interpenetrating plasmas

    Directory of Open Access Journals (Sweden)

    Davis S.

    2013-11-01

    Full Text Available Ion stream instabilities are essential for collisionless shock formation as seen in astrophysics. Weakly relativistic shocks are considered as candidates for sources of high energy cosmic rays. Laboratory experiments may provide a better understanding of this phenomenon. High intensity short pulse laser systems are opening possibilities for efficient ion acceleration to high energies. Their collision with a secondary target could be used for collisionless shock formation. In this paper, using particle-in-cell simulations we are studying interaction of a sub-relativistic, laser created proton beam with a secondary gas target. We show that the ion bunch initiates strong electron heating accompanied by the Weibel-like filamentation and ion energy losses. The energy repartition between ions, electrons and magnetic fields are investigated. This yields insight on the processes occurring in the interstellar medium (ISM and gamma-ray burst afterglows.

  14. Time Resolved Energy Transfer and Photodissociation of Vibrationally Excited Molecules

    National Research Council Canada - National Science Library

    Crim, F. F

    2007-01-01

    ...) in solution and in the gas phase. This second experiment is one of the few direct comparisons of intramolecular vibrational energy flow in a solvated molecule with that in the same molecule isolated in a gas...

  15. 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.

  16. [Mechanism of intermolecular energy transfer and reception of ultralow action by chemical and biological systems].

    Science.gov (United States)

    Gall', L N; Gall', N R

    2009-01-01

    A novel concept of intermolecular energy transfer and reception of the ultralow action in living systems is proposed. The concept is based on the methods of nonlinear mathematical physics used in description of energy movement along molecular chains and on quantum mechanical ideas concerning signal formation in anisotropic media. A concept of a molecular cell as an indivisible structural unit and a constituent of a biological (chemical) system has been put forward and substantiated, which manifests collective features of the unity of molecules, physical fields, and energetically strained bound water media in processes of energy transfer and reception. Both intermolecular energy transfer and amplification of the ultralow action has been shown to be the components of a unified energy process in a living system, and the physical basis of both processes is the unity of molecules and water-field media in a molecular cell.

  17. 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.

  18. Carrier multiplication in semiconductor nanocrystals detected by energy transfer to organic dye molecules.

    Science.gov (United States)

    Xiao, Jun; Wang, Ying; Hua, Zheng; Wang, Xiaoyong; Zhang, Chunfeng; Xiao, Min

    2012-01-01

    Carrier multiplication describes an interesting optical phenomenon in semiconductors whereby more than one electron-hole pair, or exciton, can be simultaneously generated upon absorption of a single high-energy photon. So far, it has been highly debated whether the carrier multiplication efficiency is enhanced in semiconductor nanocrystals as compared with their bulk counterpart. The controversy arises from the fact that the ultrafast optical methods currently used need to correctly account for the false contribution of charged excitons to the carrier multiplication signals. Here we show that this charged exciton issue can be resolved in an energy transfer system, where biexcitons generated in the donor nanocrystals are transferred to the acceptor dyes, leading to an enhanced fluorescence from the latter. With the biexciton Auger and energy transfer lifetime measurements, an average carrier multiplication efficiency of ~17.1% can be roughly estimated in CdSe nanocrystals when the excitation photon energy is ~2.46 times of their energy gap.

  19. Syntrophic growth with direct interspecies electron transfer as the primary mechanism for energy exchange

    DEFF Research Database (Denmark)

    Shrestha, Pravin Malla; Rotaru, Amelia-Elena; Aklujkar, Muktak

    2013-01-01

    Direct interspecies electron transfer (DIET) through biological electrical connections is an alternative to interspecies H2 transfer as a mechanism for electron exchange in syntrophic cultures. However, it has not previously been determined whether electrons received via DIET yield energy to supp...... dehydrogenase, the pilus-associated c-type cytochrome OmcS and pili consistent with electron transfer via DIET. These results suggest that electrons transferred via DIET can serve as the sole energy source to support anaerobic respiration....... to support cell growth. In order to investigate this, co-cultures of Geobacter metallireducens, which can transfer electrons to wild-type G. sulfurreducens via DIET, were established with a citrate synthase-deficient G. sulfurreducens strain that can receive electrons for respiration through DIET only...

  20. Experimental Study of RF Energy Transfer System in Indoor Environment

    Science.gov (United States)

    Adami, S.-E.; Proynov, P. P.; Stark, B. H.; Hilton, G. S.; Craddock, I. J.

    2014-11-01

    This paper presents a multi-transmitter, 2.43 GHz Radio-Frequency (RF) wireless power transfer (WPT) system for powering on-body devices. It is shown that under typical indoor conditions, the received power range spans several orders of magnitude from microwatts to milliwatts. A body-worn dual-polarised rectenna (rectifying antenna) is presented, designed for situations where the dominant polarization is unpredictable, as is the case for the on-body sensors. Power management circuitry is demonstrated that optimally loads the rectenna even under highly intermittent conditions, and boosts the voltage to charge an on-board storage capacitor.

  1. Energy transfer pathways in semiconducting carbon nanotubes revealed using two-dimensional white-light spectroscopy.

    Science.gov (United States)

    Mehlenbacher, Randy D; McDonough, Thomas J; Grechko, Maksim; Wu, Meng-Yin; Arnold, Michael S; Zanni, Martin T

    2015-04-13

    Thin film networks of highly purified semiconducting carbon nanotubes (CNTs) are being explored for energy harvesting and optoelectronic devices because of their exceptional transport and optical properties. The nanotubes in these films are in close contact, which permits energy to flow through the films, although the pathways and mechanisms for energy transfer are largely unknown. Here we use a broadband continuum to collect femtosecond two-dimensional white-light spectra. The continuum spans 500 to 1,300 nm, resolving energy transfer between all combinations of bandgap (S1) and higher (S2) transitions. We observe ultrafast energy redistribution on the S2 states, non-Förster energy transfer on the S1 states and anti-correlated energy levels. The two-dimensional spectra reveal competing pathways for energy transfer, with S2 excitons taking routes depending on the bandgap separation, whereas S1 excitons relax independent of the bandgap. These observations provide a basis for understanding and ultimately controlling the photophysics of energy flow in CNT-based devices.

  2. Exciton Energy Transfer from Halide Terminated Nanocrystals to Graphene in Solar Photovoltaics

    Science.gov (United States)

    Ajayi, Obafunso; Abramson, Justin; Anderson, Nicholas; Owen, Jonathan; Zhao, Yue; Kim, Phillip; Gesuele, Felice; Wong, Chee Wei

    2011-03-01

    Graphene, a zero-gap semiconductor, has been identified as an ideal electrode for nanocrystal solar cell photovoltaic applications due to its high carrier mobility. Further advances in efficient current extraction are required towards this end. We investigate the resonant energy transfer dynamics between photoexcited nanocrystals and graphene, where the energy transfer rate is characterized by the fluorescent quenching of the quantum dots in the presence of graphene. Energy transfer has been shown to have a d -4 dependence on the nanocrystal distance from the graphene surface, with a correction due to blinking statistics. We investigate this relationship with single and few layer graphene. We study halide-terminated CdSe quantum dots; where the absence of the insulating outershell improves the electronic coupling of the donor-acceptor system leads to improved electron transfer. We observe quenching of the halide terminated nanocrystals on graphene, with the quenching factor ρ defined as IQ /IG (the relative intensities on quartz and graphene).

  3. Parametric investigation on transient boiling heat transfer of metal rod cooled rapidly in water pool

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chi Young [Department of Fire Protection Engineering, Pukyong National University, 45, Yongso-ro, Nam-gu, Busan 48513 (Korea, Republic of); Kim, Sunwoo, E-mail: swkim@alaska.edu [Mechanical Engineering Department, University of Alaska Fairbanks, P. O. Box 755905, Fairbanks, AK 99775-5905 (United States)

    2017-03-15

    Highlights: • Effects of liquid subcooling, surface coating, material property, and surface oxidation are examined. • Liquid subcooling affects remarkably the quenching phenomena. • Cr-coated surfaces for ATF might extend the quenching duration. • Solids with low heat capacity shorten the quenching duration. • Surface oxidation can affect strongly the film boiling heat transfer and MFB point. - Abstract: In this work, the effects of liquid subcooling, surface coating, material property, and surface oxidation on transient pool boiling heat transfer were investigated experimentally using the vertical metal rod and quenching method. The change in rod temperature was measured with time during quenching, and the visualization of boiling around the test specimen was performed using the high-speed video camera. As the test materials, the zircaloy (Zry), stainless steel (SS), niobium (Nb), and copper (Cu) were tested. In addition, the chromium-coated niobium (Cr-Nb) and chromium-coated stainless steel (Cr-SS) were prepared for accident tolerant fuel (ATF) application. Low liquid subcooling and Cr-coating shifted the quenching curve to the right, which indicates a prolongation of quenching duration. On the other hand, the material with small heat capacity and surface oxidation caused the quenching curve to move to the left. To examine the influence of the material property and surface oxidation on the film boiling heat transfer performance and minimum film boiling (MFB) point in more detail, the wall temperature and heat flux were calculated from the present transient temperature profile using the inverse heat transfer analysis, and then the curves of wall temperature and heat flux in the film boiling regime were obtained. In the present experimental conditions, the effect of material property on the film boiling heat transfer performance and MFB point seemed to be minor. On the other hand, based on the experimental results of the Cu test specimen, the surface

  4. Manipulating Energy Transfer in Conjugated Polymers using Radical Mediators

    Science.gov (United States)

    Wilcox, Daniel; Mukherjee, Sanjoy; Boudouris, Bryan

    Previous efforts have demonstrated that polymers containing open-shell moieties can be used to improve the performance of organic electronic devices (e.g., organic field-effect transistors (OFETs) and photovoltaic devices). However, the exact mechanism of how these redox-active radical polymers improve the performance of these next-generation devices has yet to be described in full. Here, we take the first steps towards elucidating this full picture by demonstrating that the galvinoxyl radical can be used as an electron acceptor for a common electron-donating macromolecule. First, galvinoxyl was used as a fluorescence quencher for poly(3-hexylthiophene) (P3HT) with quenching performance on par with that of oft-used fullerene derivatives. This effect was caused by photoinduced electron transfer between the two materials. Additionally, the galvinoxyl radical was used as an active layer dopant for P3HT OFETs. By increasing the P3HT carrier density through spontaneous electron transfer, the behavior of the device was changed from that of an intrinsic semiconductor to that of a highly-doped semiconductor. Thus, these initial studies lay the foundation for a paradigm where open-shell entities are used to dope conjugated polymer semiconductors for high-performance device applications.

  5. Spatial dependence of magnetopause energy transfer: Cluster measurements verifying global simulations

    Directory of Open Access Journals (Sweden)

    M. Palmroth

    2011-05-01

    Full Text Available We investigate the spatial variation of magnetopause energy conversion and transfer using Cluster spacecraft observations of two magnetopause crossing events as well as using a global magnetohydrodynamic (MHD simulation GUMICS-4. These two events, (16 January 2001, and 26 January 2001 are similar in all other aspects except for the sign of the interplanetary magnetic field (IMF y-component that has earlier been found to control the spatial dependence of energy transfer. In simulations of the two events using observed solar wind parameters as input, we find that the GUMICS-4 energy transfer agrees with the Cluster observations spatially and is about 30 % lower in magnitude. According to the simulation, most of the the energy transfer takes place in the plane of the IMF (as previous modelling results have suggested, and the locations of the load and generator regions on the magnetopause are controlled by the IMF orientation. Assuming that the model results are as well in accordance with the in situ observations also on other parts of the magnetopause, we are able to pin down the total energy transfer during the two Cluster magnetopause crossings. Here, we estimate that the instantaneous total power transferring through the magnetopause during the two events is at least 1500–2000 GW, agreeing with ε scaled using the mean magnetopause area in the simulation. Hence the combination of the simulation results and the Cluster observations indicate that the ε parameter is probably underestimated by a factor of 2–3.

  6. Rapid tomato volatile profiling by using proton-transfer reaction mass spectrometry (PTS-MS)

    NARCIS (Netherlands)

    Farneti, B.; Cristescu, S.M.; Costa, G.; Harren, F.J.M.; Woltering, E.J.

    2012-01-01

    The availability of rapid and accurate methods to assess fruit flavor is of utmost importance to support quality control especially in the breeding phase. Breeders need more information and analytical tools to facilitate selection for complex multigenic traits such as flavor quality. In this study,

  7. Remote Electric Power Transfer Between Spacecrafts by Infrared Beamed Energy

    Science.gov (United States)

    Chertok, Boris E.; Evdokimov, Roman A.; Legostaev, Victor P.; Lopota, Vitaliy A.; Sokolov, Boris A.; Tugaenko, Vjacheslav Yu.

    2011-11-01

    High efficient wireless electric energy transmission (WET) technology between spacecrafts by laser channel is proposed. WET systems could be used for remote power supplying of different consumers in space. First of all, there are autonomous technology modules for microgravity experiments, micro and nano satellites, different equipment for explorations of planetary surfaces, space transport vehicles with electric rocket propulsion systems. The main components of the WET technology consist of radiation sources on the base of semiconductor IR laser diodes; systems for narrow laser beam creation; special photovoltaic receivers for conversion of monochromatic IR radiation with high energy density to electric power. The multistage space experiment for WET technology testing is described. During this experiment energy will be transmitted from International Space Station to another spacecrafts like cargo transport vehicles (Progress or/and ATV) and micro satellites.

  8. Solar-pumped electronic-to-vibrational energy transfer lasers

    Science.gov (United States)

    Harries, W. L.; Wilson, J. W.

    1981-01-01

    The possibility of using solar-pumped lasers as solar energy converters is examined. The absorbing media considered are halogens or halogen compounds, which are dissociated to yield excited atoms, which then hand over energy to a molecular lasing medium. Estimates of the temperature effects for a Br2-CO2-He system with He as the cooling gas are given. High temperatures can cause the lower energy levels of the CO2 laser transition to be filled. The inverted populations are calculated and lasing should be possible. However, the efficiency is less than 0.001. Examination of other halogen-molecular lasant combinations (where the rate coefficients are known) indicate efficiencies in all cases of less than 0.005.

  9. Rapid nitrogen transfer in the Sorghum bicolor-Glomus mosseae arbuscular mycorrhizal symbiosis.

    Science.gov (United States)

    Koegel, Sally; Boller, Thomas; Lehmann, Moritz F; Wiemken, Andres; Courty, Pierre-Emmanuel

    2013-08-01

    We have recently identified two genes coding for ammonium transporters (AMT) in Sorghum bicolor that were induced in roots colonized by arbuscular mycorrhizal (AM) fungi. To improve our understanding of the dynamics of ammonium transport in this symbiosis, we studied the transfer of soil-ammonium-derived (15)N to S. bicolor plants via the Glomus mosseae fungal mycelium in compartmented microcosms. The (15)NH (4+)-containing hyphal compartment was inaccessible to the roots in the plant compartment. (15)N label concentrations significantly increased in plant roots and leaves already 48 h after exposure of the AM fungus to the (15)NH (4+) substrate, attesting an efficient symbiotic N transfer between the symbiotic partners and further highlighting that AM symbiosis represents an important component of plant nitrogen nutrition.

  10. 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.

  11. 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.

  12. 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.

  13. Local shell-to-shell energy transfer via nonlocal interactions in fluid ...

    Indian Academy of Sciences (India)

    in a triad, and the energy exchanges between wave-number shells in incompressible fluid turbulence. The computation has been done using first-order perturbative field theory. In three dimensions, magnitude of triad interactions is large for nonlocal triads, and small for local triads. However, the shell-to-shell energy transfer ...

  14. A schematic model for energy and charge transfer in the chlorophyll complex

    DEFF Research Database (Denmark)

    Bohr, Henrik; Malik, F.B.

    2011-01-01

    -chlorophylls chromophore to the reaction center by sending an electromagnetic wave (a photon) which provides a novel new mechanism for energy production. In the simplest version of the Förster–Dexter theory, the excitation energy of a donor is transferred to an acceptor and then de-excited to the ground state...

  15. Rotational energy transfer of the A{sup 2}{Sigma}`({nu}`=1) state of OH

    Energy Technology Data Exchange (ETDEWEB)

    Beaud, P.; Radi, P.; Frey, H.B.; Mischler, B.; Tzannis, A.P.; Gerber, T. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Spectrally and temporally resolved laser excited fluorescence of OH is investigated in the picosecond time domain. The total rotational energy transfer (RET) rate from the excited state is determined from the experimental data. Simulated spectra obtained by modelling RET with the energy corrected sudden approximation agree well with the measured spectra. (author) 1 fig., 1 tab., 5 refs.

  16. Generating Excitement: Build Your Own Generator to Study the Transfer of Energy

    Science.gov (United States)

    Fletcher, Kurt; Rommel-Esham, Katie; Farthing, Dori; Sheldon, Amy

    2011-01-01

    The transfer of energy from one form to another can be difficult to understand. The electrical energy that turns on a lamp may come from the burning of coal, water falling at a hydroelectric plant, nuclear reactions, or gusts of wind caused by the uneven heating of the Earth. The authors have developed and tested an exciting hands-on activity to…

  17. A Conceptual Change Model for Teaching Heat Energy, Heat Transfer and Insulation

    Science.gov (United States)

    Lee, C. K.

    2014-01-01

    This study examines the existing knowledge that pre-service elementary teachers (PSETs) have regarding heat energy, heat transfer and insulation. The PSETs' knowledge of heat energy was initially assessed by using an activity: determining which container would be best to keep hot water warm for the longest period of time. Results showed that PSETs…

  18. Drawing Lessons When Objectives Differ? Assessing Renewable Energy Policy Transfer from Germany to Morocco

    Directory of Open Access Journals (Sweden)

    Karoline Steinbacher

    2015-05-01

    Full Text Available Given the tremendous energy challenges Morocco faces, and its potential role as an exporter of green electricity to Europe, the country has been particularly targeted by Germany’s efforts to promote the uptake of renewable energies abroad. This paper explores whether ideas and policies in the field of renewable energy effectively traveled through transfer channels established between Germany and Morocco. In particular, the question of how Morocco’s policy objectives shaped the result of transfer processes is discussed, shedding light on a currently under-researched determinant for policy transfer. Drawing upon forty-five semi-structured interviews with Moroccan, German, and international stakeholders, as well as card-ranking exercises, the article provides first-hand insights into the dynamics and drivers of Morocco’s “energy transition”. Findings presented in the article show that differing policy objectives did not preclude the transfer of ideas between Germany and Morocco, but shaped its outcome with regard to policy instrument selection. While basic policy orientations in favour of renewable energies were facilitated by transferred knowledge, a perceived incompatibility between domestic policy objectives and the policy instruments used in the foreign model led to selective lesson-drawing from the German example. This finding underlines the importance for “senders” who wish to actively promote sustainable energy policies abroad to adapt outreach strategies to the policy objectives of potential followers.

  19. Role of an elliptical structure in photosynthetic energy transfer: Collaboration between quantum entanglement and thermal fluctuation.

    Science.gov (United States)

    Oka, Hisaki

    2016-05-13

    Recent experiments have revealed that the light-harvesting complex 1 (LH1) in purple photosynthetic bacteria has an elliptical structure. Generally, symmetry lowering in a structure leads to a decrease in quantum effects (quantum coherence and entanglement), which have recently been considered to play a role in photosynthetic energy transfer, and hence, elliptical structure seems to work against efficient photosynthetic energy transfer. Here we analyse the effect of an elliptical structure on energy transfer in a purple photosynthetic bacterium and reveal that the elliptical distortion rather enhances energy transfer from peripheral LH2 to LH1 at room temperature. Numerical results show that quantum entanglement between LH1 and LH2 is formed over a wider range of high energy levels than would have been the case with circular LH1. Light energy absorbed by LH2 is thermally pumped via thermal fluctuation and is effectively transferred to LH1 through the entangled states at room temperature rather than at low temperature. This result indicates the possibility that photosynthetic systems adopt an elliptical structure to effectively utilise both quantum entanglement and thermal fluctuation at physiological temperature.

  20. The impulsive effects of momentum transfer on the dynamics of a novel ocean wave energy converter

    Science.gov (United States)

    Diamond, Christopher A.; O'Reilly, Oliver M.; Savaş, Ömer

    2013-10-01

    In a recent paper by Orazov et al. [On the dynamics of a novel ocean wave energy converter. Journal of Sound and Vibration329 (24) (2010) 5058-5069], a wave energy converter (WEC) was proposed. The converter features a mass modulation scheme and a simple model was used to examine its efficacy. The simple model did not adequately account for the momentum transfer which takes place during the mass modulation. The purpose of the present paper is to account for this transfer and to show that the WEC equipped with a novel and more general mass modulation scheme has the potential to improve its energy harvesting capabilities.

  1. Radiative energy transfer from MoS2 excitons to surface plasmons

    Science.gov (United States)

    Kang, Yimin; Li, Bowen; Fang, Zheyu

    2017-12-01

    In this work, we demonstrated the energy transfer process from few-layer MoS2 to gold dimer arrays via ultrafast pump-probe spectroscopy. With the overlap between the MoS2 exciton and the designed plasmon dipolar modes in the frequency domain, the exciton energy can be radiatively transferred to plasmonic structures, excited the localized surface plasmon resonance, and then enhanced the oscillation of coherent acoustic phonons. Power-dependent differential reflection signals and an analytical model based on the rate equation of exciton density were carried out to quantitatively study the energy transfer process. Our finding explores the energy flow between MoS2 excitons and surface plasmons, and can be contributed to the design of exciton-plasmon structures utilizing ultrathin materials.

  2. Numerical simulation of heat transfer in microchannel using energy conservative dissipative particle dynamics

    Directory of Open Access Journals (Sweden)

    Yelei Xie

    2015-03-01

    Full Text Available Dissipative particle dynamics is a particle-based mesoscopic simulation method. Classic dissipative particle dynamics cannot be used to simulate heat transfer in fluids since the total energy of the system is not conserved. In this article, two-dimensional unsteady heat conduction is first investigated using dissipative particle dynamics with energy conservation. The energy conservative dissipative particle dynamics results are compared with the FLUENT simulation data, and it demonstrates that they are in good agreement with each other. Then, forced convection heat transfers in microchannel of the same wall temperature and different wall temperatures are simulated, respectively, by using periodic boundary condition of dimensionless temperature. The results show that the velocity, temperature, and dimensionless temperature distributions are consistent with theoretical results. Finally, we give a qualitative analysis about the applicability of the energy conservative dissipative particle dynamics approach in simulating flow and heat transfer in rough microchannel.

  3. A simple model for exploring the role of quantum coherence and the environment in excitonic energy transfer.

    Science.gov (United States)

    Manikandan, Sreenath K; Shaji, Anil

    2015-07-28

    We investigate the role of quantum coherence in modulating the energy transfer rate between two independent energy donors and a single acceptor participating in an excitonic energy transfer process. The energy transfer rate depends explicitly on the nature of the initial coherent superposition state of the two donors and we connect it to the observed absorption profile of the acceptor and the stimulated emission profile of the energy donors. We consider simple models with mesoscopic environments interacting with the donors and the acceptor and compare the expression we obtained for the energy transfer rate with the results of numerical integration.

  4. Transfer RNAs Mediate the Rapid Adaptation of Escherichia coli to Oxidative Stress

    Science.gov (United States)

    Du, Gaofei; Sun, Xuesong; He, Qing-Yu; Zhang, Gong

    2015-01-01

    Translational systems can respond promptly to sudden environmental changes to provide rapid adaptations to environmental stress. Unlike the well-studied translational responses to oxidative stress in eukaryotic systems, little is known regarding how prokaryotes respond rapidly to oxidative stress in terms of translation. In this study, we measured protein synthesis from the entire Escherichia coli proteome and found that protein synthesis was severely slowed down under oxidative stress. With unchanged translation initiation, this slowdown was caused by decreased translation elongation speed. We further confirmed by tRNA sequencing and qRT-PCR that this deceleration was caused by a global, enzymatic downregulation of almost all tRNA species shortly after exposure to oxidative agents. Elevation in tRNA levels accelerated translation and protected E. coli against oxidative stress caused by hydrogen peroxide and the antibiotic ciprofloxacin. Our results showed that the global regulation of tRNAs mediates the rapid adjustment of the E. coli translation system for prompt adaptation to oxidative stress. PMID:26090660

  5. Low-energy plasma immersion ion implantation to induce DNA transfer into bacterial E. coli

    Energy Technology Data Exchange (ETDEWEB)

    Sangwijit, K. [Biotechnology Unit, University of Phayao, Muang, Phayao 56000 (Thailand); Yu, L.D., E-mail: yuld@thep-center.org [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Sarapirom, S. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Bang Khen, Chiang Mai 50290 (Thailand); Pitakrattananukool, S. [School of Science, University of Phayao, Muang, Phayao 56000 (Thailand); Anuntalabhochai, S. [Biotechnology Unit, University of Phayao, Muang, Phayao 56000 (Thailand)

    2015-12-15

    Plasma immersion ion implantation (PIII) at low energy was for the first time applied as a novel biotechnology to induce DNA transfer into bacterial cells. Argon or nitrogen PIII at low bias voltages of 2.5, 5 and 10 kV and fluences ranging from 1 × 10{sup 12} to 1 × 10{sup 17} ions/cm{sup 2} treated cells of Escherichia coli (E. coli). Subsequently, DNA transfer was operated by mixing the PIII-treated cells with DNA. Successes in PIII-induced DNA transfer were demonstrated by marker gene expressions. The induction of DNA transfer was ion-energy, fluence and DNA-size dependent. The DNA transferred in the cells was confirmed functioning. Mechanisms of the PIII-induced DNA transfer were investigated and discussed in terms of the E. coli cell envelope anatomy. Compared with conventional ion-beam-induced DNA transfer, PIII-induced DNA transfer was simpler with lower cost but higher efficiency.

  6. Indoor Wireless RF Energy Transfer for Powering Wireless Sensors

    Directory of Open Access Journals (Sweden)

    H. Visser

    2012-12-01

    Full Text Available For powering wireless sensors in buildings, rechargeable batteries may be used. These batteries will be recharged remotely by dedicated RF sources. Far-field RF energy transport is known to suffer from path loss and therefore the RF power available on the rectifying antenna or rectenna will be very low. As a consequence, the RF-to-DC conversion efficiency of the rectenna will also be very low. By optimizing not only the subsystems of a rectenna but also taking the propagation channel into account and using the channel information for adapting the transmit antenna radiation pattern, the RF energy transport efficiency will be improved. The rectenna optimization, channel modeling and design of a transmit antenna are discussed.

  7. Drawing Lessons When Objectives Differ? Assessing Renewable Energy Policy Transfer from Germany to Morocco

    OpenAIRE

    Steinbacher, Karoline

    2015-01-01

    Given the tremendous energy challenges Morocco faces, and its potential role as an exporter of green electricity to Europe, the country has been particularly targeted by Germany’s efforts to promote the uptake of renewable energies abroad. This paper explores whether ideas and policies in the field of renewable energy effectively traveled through transfer channels established between Germany and Morocco. In particular, the question of how Morocco’s policy objectives shaped the result of trans...

  8. Nature does not rely on long-lived electronic quantum coherence for photosynthetic energy transfer

    Science.gov (United States)

    Duan, Hong-Guang; Prokhorenko, Valentyn I.; Cogdell, Richard J.; Ashraf, Khuram; Stevens, Amy L.; Thorwart, Michael; Miller, R. J. Dwayne

    2017-08-01

    During the first steps of photosynthesis, the energy of impinging solar photons is transformed into electronic excitation energy of the light-harvesting biomolecular complexes. The subsequent energy transfer to the reaction center is commonly rationalized in terms of excitons moving on a grid of biomolecular chromophores on typical timescales light-harvesting complexes, we anticipate that this finding is general and directly applies to even larger photoactive biomolecular complexes.

  9. Quantum Transfer Energy and Nonlocal Correlation in a Dimer with Time-Dependent Coupling Effect

    Science.gov (United States)

    El-Shishtawy, Reda M.; Berrada, K.; C. Haddon, Robert; Al-Hadeethi, Yas F.; H. Al-Heniti, Saleh.; Raffah, Bahaaudin M.

    2017-05-01

    The presence of coherence phenomenon due to the interference of probability amplitude terms, is one of the most important features of quantum mechanics theory. Recent experiments show the presence of quantum processes whose coherence provided over suddenly large interval-time. In particular, photosynthetic mechanisms in light-harvesting complexes provide oscillatory behaviors in quantum mechanics due to quantum coherence. In this work, we investigate the coherent quantum transfer energy for a single-excitation and nonlocal correlation in a dimer system modelled by a two-level atom system with and without time-dependent coupling effect. We analyze and explore the required conditions that are feasible with real experimental realization for optimal transfer of quantum energy and generation of nonlocal quantum correlation. We show that the enhancement of the probability for a single-excitation transfer energy is greatly benefits from the combination of the energy detuning and time-dependent coupling effect. We investigate the presence of quantum correlations in the dimer using the entanglement of formation. We also find that the entanglement between the donor and acceptor is very sensitive to the physical parameters and it can be generated during the coherent energy transfer. On the other hand, we study the dynamical behavior of the quantum variance when performing a measurement on an observable of the density matrix operator. Finally, an interesting relationship between the transfer probability, entanglement and quantum variance is explored during the time evolution in terms of the physical parameters.

  10. Energy transfer studies of dye chromophores in modified zirconium phosphate framework

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qing; Yan, Haijiao; Su, Yumin [College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang 050024, Hebei Province (China); Shi, Shikao, E-mail: ssk02@mails.tsinghua.edu.cn [College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang 050024, Hebei Province (China); Ye, Jianping [Key Laboratory of Photochemistry, Institute of Chemistry Chinese Academy of Science, Beijing 100080 (China)

    2014-08-01

    In this paper, a layered inorganic compound—modified zirconium phosphate was used as a framework to assemble fluorescein and rhodamine B dye chromophores. After the dye chromophores were bound to the layered framework, the evident energy transfer process from fluorescein (donor) to rhodamine B (acceptor) was observed, resulting in the dramatic luminescence enhancement for rhodamine B. Without the framework, such energy transfer was absent in aqueous solutions. The results manifest that the lamellar inorganic framework can provide suitable microenvironment to organize the dye chromophores in elaborate arrangements, and promote the intermolecular energy transfer. In addition, the fluorescent lifetime of the donor in different surroundings was analyzed, which further confirmed the energy transfer via a nonradiative process. - Highlights: • A modified zirconium phosphate was applied as a framework to assemble dye chromophores. • After Fl and RhB dyes were bound to the framework, the luminescence intensity for RhB dye was greatly enhanced. • The energy transfer process from Fl to RhB was confirmed in the framework. • The result is useful in the design of light harvesting complexes and photon antennas.

  11. Rapid transfer of photosynthetic carbon through the plant-soil system in differently managed species-rich grasslands

    Directory of Open Access Journals (Sweden)

    G. B. De Deyn

    2011-05-01

    Full Text Available Plant-soil interactions are central to short-term carbon (C cycling through the rapid transfer of recently assimilated C from plant roots to soil biota. In grassland ecosystems, changes in C cycling are likely to be influenced by land use and management that changes vegetation and the associated soil microbial communities. Here we tested whether changes in grassland vegetation composition resulting from management for plant diversity influences short-term rates of C assimilation and transfer from plants to soil microbes. To do this, we used an in situ 13C-CO2 pulse-labelling approach to measure differential C uptake among different plant species and the transfer of the plant-derived 13C to key groups of soil microbiota across selected treatments of a long-term plant diversity grassland restoration experiment. Results showed that plant taxa differed markedly in the rate of 13C assimilation and concentration: uptake was greatest and 13C concentration declined fastest in Ranunculus repens, and assimilation was least and 13C signature remained longest in mosses. Incorporation of recent plant-derived 13C was maximal in all microbial phosopholipid fatty acid (PLFA markers at 24 h after labelling. The greatest incorporation of 13C was in the PLFA 16:1ω5, a marker for arbuscular mycorrhizal fungi (AMF, while after 1 week most 13C was retained in the PLFA18:2ω6,9 which is indicative of assimilation of plant-derived 13C by saprophytic fungi. Our results of 13C assimilation and transfer within plant species and soil microbes were consistent across management treatments. Overall, our findings suggest that plant diversity restoration management may not directly affect the C assimilation or retention of C by individual plant taxa or groups of soil microbes, it can impact on the fate of recent C by changing their relative abundances

  12. Energy transfer during freeze-drying in dual-chamber cartridges.

    Science.gov (United States)

    Korpus, Christoph; Haase, Thomas; Sönnichsen, Caren; Friess, Wolfgang

    2015-05-01

    Freeze-drying essentially requires knowledge about the heat and mass transfer characteristics to assure product quality. Whereas this understanding has been created for freeze-drying in vials, only limited information is available for state-of-the-art multiple compartment container systems such as dual-chamber cartridges (DCCs). Therefore, the aim of this study was to investigate the heat transfer characteristics of this novel container format. Sublimation tests were carried out using pure water at 60, 100, 150, and 200 mTorr chamber pressure at a shelf temperature of 0°C. Custom-made aluminum blocks were used as holder systems. Two heat transfer coefficients could be identified: the coefficient characterizing heat transfer between shelf and block, KAl , and between block and cartridge, KDCC . KAl was dependent on all three modes of heat transfer: contact conduction, gas conduction, and radiation. For KDCC , contact conduction was negligible. Radiation strongly influenced the overall energy transfer as it is the major mode of heat transfer for KDCC and contributes up to 44% to KAl . A third coefficient, Ktot , was defined as an overall heat transfer coefficient. This knowledge about heat transfer enables a purposeful development and control of optimized lyophilization processes for this novel container system. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  13. [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.

  14. Energy transfer and clustering of photosynthetic light-harvesting complexes in reconstituted lipid membranes

    Energy Technology Data Exchange (ETDEWEB)

    Dewa, Takehisa, E-mail: takedewa@nitech.ac.jp [Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Japan Science and Technology, PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 332-0012 (Japan); Sumino, Ayumi; Watanabe, Natsuko; Noji, Tomoyasu [Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Nango, Mamoru, E-mail: nango@nitech.ac.jp [Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan)

    2013-06-20

    Highlights: ► Photosynthetic light-harvesting complexes were reconstituted into lipid membranes. ► Energy transfers between light-harvesting complexes were examined. ► Atomic force microscopy indicated cluster formation of light-harvesting complexes. ► Efficient energy transfer was observed for the clustered complexes in the membranes. - Abstract: In purple photosynthetic bacteria, light-harvesting complex 2 (LH2) and light harvesting/reaction centre core complex (LH1-RC) play the key roles of capturing and transferring light energy and subsequent charge separation. These photosynthetic apparatuses form a supramolecular assembly; however, how the assembly influences the efficiency of energy conversion is not yet clear. We addressed this issue by evaluating the energy transfer in reconstituted photosynthetic protein complexes LH2 and LH1-RC and studying the structures and the membrane environment of the LH2/LH1-RC assemblies, which had been embedded into various lipid bilayers. Thus, LH2 and LH1-RC from Rhodopseudomonas palustris 2.1.6 were reconstituted in phosphatidylglycerol (PG), phosphatidylcholine (PC), and phosphatidylethanolamine (PE)/PG/cardiolipin (CL). Efficient energy transfer from LH2 to LH1-RC was observed in the PC and PE/PG/CL membranes. Atomic force microscopy revealed that LH2 and LH1-RC were heterogeneously distributed to form clusters in the PC and PE/PG/CL membranes. The results indicated that the phospholipid species influenced the cluster formation of LH2 and LH1-RC as well as the energy transfer efficiency.

  15. Rapid stress system drives chemical transfer of fear from sender to receiver.

    Directory of Open Access Journals (Sweden)

    Jasper H B de Groot

    Full Text Available Humans can register another person's fear not only with their eyes and ears, but also with their nose. Previous research has demonstrated that exposure to body odors from fearful individuals elicited implicit fear in others. The odor of fearful individuals appears to have a distinctive signature that can be produced relatively rapidly, driven by a physiological mechanism that has remained unexplored in earlier research. The apocrine sweat glands in the armpit that are responsible for chemosignal production contain receptors for adrenalin. We therefore expected that the release of adrenalin through activation of the rapid stress response system (i.e., the sympathetic-adrenal medullary system is what drives the release of fear sweat, as opposed to activation of the slower stress response system (i.e., hypothalamus-pituitary-adrenal axis. To test this assumption, sweat was sampled while eight participants prepared for a speech. Participants had higher heart rates and produced more armpit sweat in the fast stress condition, compared to baseline and the slow stress condition. Importantly, exposure to sweat from participants in the fast stress condition induced in receivers (N = 31 a simulacrum of the state of the sender, evidenced by the emergence of a fearful facial expression (facial electromyography and vigilant behavior (i.e., faster classification of emotional facial expressions.

  16. Topics in design and analysis of transcutaneous energy transfer to ventricular assist devices.

    OpenAIRE

    Daniela Wolter Ferreira

    2013-01-01

    This research studies a Transcutaneous Energy Transfer (TET) system which uses electromagnetic fields to transfer power from outside the body to an artificial organ (AO) in the body. It works like a high frequency transformer whereas the skin is part of the magnetic coupling between the primary (external) and secondary (internal) coils. Thus, the external coil (transmitter), which is excited by an oscillator circuit that transforms the continuous (DC) voltage to high-frequency alternating (AC...

  17. Theoretical Analysis for Heat Transfer Optimization in Subcritical Electrothermal Energy Storage Systems

    OpenAIRE

    Peng Hu; Gao-Wei Zhang; Long-Xiang Chen; Ming-Hou Liu

    2017-01-01

    Electrothermal energy storage (ETES) provides bulk electricity storage based on heat pump and heat engine technologies. A subcritical ETES is described in this paper. Based on the extremum principle of entransy dissipation, a geometry model is developed for heat transfer optimization for subcritical ETES. The exergy during the heat transfer process is deduced in terms of entropy production. The geometry model is validated by the extremum principle of entropy production. The theoretical analys...

  18. Rapid and inexpensive fabrication of polymeric microfluidic devices via toner transfer masking

    Science.gov (United States)

    Easley, Christopher J.; Benninger, Richard K. P.; Shaver, Jesse H.; Head, W. Steven; Piston, David W.

    2009-01-01

    Summary An alternative fabrication method is presented for production of masters for single- or multilayer polymeric microfluidic devices in a standard laboratory environment, precluding the need for a cleanroom. This toner transfer masking (TTM) method utilizes an office laser printer to generate a toner pattern which is thermally transferred to a metal master to serve as a mask for etching. With master fabrication times as little as one hour (depending on channel depth) using commercially-available equipment and supplies, this approach should make microfluidic technology more widely accessible to the non-expert—even the non-scientist. The cost of fabrication consumables was estimated to be < $1 per master, over an order of magnitude decrease in consumable costs compared to standard photolithography. In addition, the use of chemical etching allows accurate control over the height of raised features (i.e., channel depths), allowing the flexibility to fabricate multiple depths on a single master with little added time. Resultant devices are shown capable of pneumatic valving, three-dimensional channel formation (using layer-connecting vias), droplet fluidics, and cell imaging and staining. The multiple-depth capabilities of the method are proven useful for cellular analysis by fabrication of handheld, disposable devices used for trapping and imaging of live murine pancreatic islets. The precise fluidic control provided by the microfluidic platform allows subsequent fixing and staining of these cells without significant movement, thus spatial correlation of imaging and staining is attainable—even with rare alpha cells that constitute only ∼10% of the islet cells. PMID:19350094

  19. Charge transfer and association of Na+ with 87Rb atoms from extremely low to intermediate energies

    Science.gov (United States)

    Yan, L. L.; Liu, L.; Wu, Y.; Qu, Y. Z.; Wang, J. G.; Buenker, R. J.

    2013-07-01

    The nonradiative charge-transfer processes in Na++87Rb(5s) collisions have been investigated by using the quantum-mechanical molecular-orbital close-coupling method and the two-center atomic-orbital close-coupling method for the energy range of 10-4-5 and 0.3-100 keV/u, respectively. The radiative charge-transfer, radiative-decay, and radiative-association processes have been investigated by using the fully quantum, optical-potential, and semiclassical methods for the energy range of 10-18-0.2 eV/u. The nonradiative charge-transfer processes dominate the collisions for energies above 0.2 eV/u and radiative-decay processes dominate in the lower-energy region. At the very low collision energies of 10-18-10-3 eV/u, the radiative-association process is more important than the radiative charge-transfer process. Most importantly, it is found that the radiative cross sections exhibit Langevin behavior as E-1/2 for energies less than 10-2 eV/u.

  20. New model of calculating the energy transfer efficiency for the spherical theta-pinch device

    CERN Document Server

    Xu, G; Loisch, G; Xiao, G; Jacoby, J; Weyrich, K; Li, Y; Zhao, Y

    2015-01-01

    Ion-beam-plasma-interaction plays an important role in the field of Warm Dense Matter (WDM) and Inertial Confinement Fusion (ICF). A spherical theta pinch is proposed to act as a plasma target in various applications including a plasma stripper cell. One key parameter for such applications is the free electron density. A linear dependency of this density to the amount of energy transferred into the plasma from an energy storage was found by C. Teske. Since the amount of stored energy is known, the energy transfer efficiency is a reliable parameter for the design of a spherical theta pinch device. The traditional two models of energy transfer efficiency are based on assumptions which comprise the risk of systematical errors. To obtain precise results, this paper proposes a new model without the necessity of any assumption to calculate the energy transfer efficiency for an inductively coupled plasma device. Further, a comparison of these three different models is given at a fixed operation voltage for the full ...

  1. Energy Transfer with Hydrogen and Superconductivity - The Review of the First Experimental Results

    Science.gov (United States)

    Vysotsky, V. S.; Antyukhov, I. V.; Firsov, V. P.; Blagov, E. V.; Kostyuk, V. V.; Nosov, A. A.; Fetisov, S. S.; Zanegin, S. Yu.; Rachuk, V. S.; Katorgin, B. I.

    The transfer of massive amounts of both electrical and chemical power over long distances will present a major challenge for the global energy enterprise in future. Attraction of hydrogen is apparent as a chemical energy agent, possessing among the highest energy density content of various common fuels, whose combustive "waste" is simply water. The usage of "gratis" cold to cool a superconducting cable made of proper superconductor permits to deliver extra electrical power with the same line. This, rather old theoretical idea recently found its experimental realization. The team of Russian institutes and organizations with using Italian-produced MgB2 wire has made and successfully tested two hybrid energy transfer lines with liquid hydrogen as a chemical source of power and superconducting cable as a source of electricity. The first line has been tested in 2011. It has length ∼10 m, maximum liquid hydrogen flow ∼250 g/s and maximum current of MgB2 superconducting cable 2600 A @ 20K. This test was the first experimental proof of conception of the hybrid energy transfer line. The second line has been tested in October 2013. It has length ∼30 m. The new MgB2 cable has critical current at 21 K ∼3500 A and successfully passed high voltage DC test of 50 kV. New hydrogen cryostat has three sections with different types of thermal insulation in each section. The idea of hybrid energy transfer is formulated and details of first experiments are reviewed.

  2. Energy transfer in the nonequilibrium spin-boson model: From weak to strong coupling.

    Science.gov (United States)

    Liu, Junjie; Xu, Hui; Li, Baowen; Wu, Changqin

    2017-07-01

    To explore energy transfer in the nonequilibrium spin-boson model (NESB) from weak to strong system-bath coupling regimes, we propose a polaron-transformed nonequilibrium Green's function (NEGF) method. By combining the polaron transformation, we are able to treat the system-bath coupling nonperturbatively, thus in direct contrast to conventionally used NEGF methods which take the system-bath coupling as a perturbation. The Majorana-fermion representation is further utilized to evaluate terms in the Dyson series. This method not only allows us to deal with weak as well as strong coupling regimes but also enables an investigation on the role of bias in the energy transfer. As an application of the method, we study an Ohmic NESB. For an unbiased spin system, our energy current result smoothly bridges predictions of two benchmarks, namely, the quantum master equation and the nonequilibrium noninteracting blip approximation, a considerable improvement over existing theories. In case of a biased spin system, we found a bias-induced nonmonotonic behavior of the energy conductance in the intermediate coupling regime, resulting from the resonant character of the energy transfer. This finding may offer a nontrivial quantum control knob over energy transfer at the nanoscale.

  3. 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.

  4. Direct observation of multistep energy transfer in LHCII with fifth-order 3D electronic spectroscopy

    Science.gov (United States)

    Zhang, Zhengyang; Lambrev, Petar H.; Wells, Kym L.; Garab, Győző; Tan, Howe-Siang

    2015-07-01

    During photosynthesis, sunlight is efficiently captured by light-harvesting complexes, and the excitation energy is then funneled towards the reaction centre. These photosynthetic excitation energy transfer (EET) pathways are complex and proceed in a multistep fashion. Ultrafast two-dimensional electronic spectroscopy (2DES) is an important tool to study EET processes in photosynthetic complexes. However, the multistep EET processes can only be indirectly inferred by correlating different cross peaks from a series of 2DES spectra. Here we directly observe multistep EET processes in LHCII using ultrafast fifth-order three-dimensional electronic spectroscopy (3DES). We measure cross peaks in 3DES spectra of LHCII that directly indicate energy transfer from excitons in the chlorophyll b (Chl b) manifold to the low-energy level chlorophyll a (Chl a) via mid-level Chl a energy states. This new spectroscopic technique allows scientists to move a step towards mapping the complete complex EET processes in photosynthetic systems.

  5. Plasmon-enhanced energy transfer for improved upconversion of infrared radiation in doped-lanthanide nanocrystals.

    Science.gov (United States)

    Sun, Qi-C; Mundoor, Haridas; Ribot, Josep C; Singh, Vivek; Smalyukh, Ivan I; Nagpal, Prashant

    2014-01-08

    Upconversion of infrared radiation into visible light has been investigated for applications in photovoltaics and biological imaging. However, low conversion efficiency due to small absorption cross-section for infrared light (Yb(3+)), and slow rate of energy transfer (to Er(3+) states) has prevented application of upconversion photoluminescence (UPL) for diffuse sunlight or imaging tissue samples. Here, we utilize resonant surface plasmon polaritons (SPP) waves to enhance UPL in doped-lanthanide nanocrystals. Our analysis indicates that SPP waves not only enhance the electromagnetic field, and hence weak Purcell effect, but also increase the rate of resonant energy transfer from Yb(3+) to Er(3+) ions by 6 fold. While we do observe strong metal mediated quenching (14-fold) of green fluorescence on flat metal surfaces, the nanostructured metal is resonant in the infrared and hence enhances the nanocrystal UPL. This strong Coulombic effect on energy transfer can have important implications for other fluorescent and excitonic systems too.

  6. Foreign Direct Investment and the Transfer of Technologies to Angola’s Energy Sector

    Directory of Open Access Journals (Sweden)

    Albert Edgar Manyuchi

    2016-01-01

    Full Text Available The relationship between foreign direct investment (FDI and the transfer of technology is undergoing a great deal of academic scrutiny and policy analysis. A growing body of literature shows that FDI can be a channel by which to transfer and/or acquire technology; however, there is a paucity of empirical studies on this as it relates to African economies. This article seeks to fill some of that gap by focusing on how FDI inflows are contributing to the transfer of technologies specifically into Angola’s energy sector. The analysis is based on qualitative research conducted in Angola in 2014 and reveals that energy production and distribution-technology infrastructure, including machinery and human skills, have been developed largely through FDI inflows. There is, however, no evidence that this FDI has enlarged Angola’s endogenous scientific and technological research capabilities in the energy sector; therefore, policies that promote these capabilities, especially manufacturing capabilities, should be introduced.

  7. Accounting for delay of energy transfer between coupled rooms in statistical-acoustics models of reverberant-energy decay.

    Science.gov (United States)

    Summers, Jason E

    2012-08-01

    A statistical-acoustics model for energy decay in systems of two or more coupled rooms is introduced, which accounts for the distribution of delay in the transfer of energy between subrooms that results from the finite speed of sound. The method extends previous models based on systems of coupled ordinary differential equations by using functional differential equations to explicitly model dependence on prior values of energy in adjacent subrooms. Predictions of the model are illustrated for a two-room coupled system and compared with the predictions of a benchmark computational geometrical-acoustics model.

  8. Chirality and energy transfer amplified circularly polarized luminescence in composite nanohelix

    OpenAIRE

    Yang, Dong; Duan, Pengfei; Zhang, Li; Liu, Minghua

    2017-01-01

    Transfer of both chirality and energy information plays an important role in biological systems. Here we show a chiral donor ?-gelator and assembled it with an achiral ?-acceptor to see how chirality and energy can be transferred in a composite donor?acceptor system. It is found that the individual chiral gelator can self-assemble into nanohelix. In the presence of the achiral acceptor, the self-assembly can also proceed and lead to the formation of the composite nanohelix. In the composite n...

  9. 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.

  10. A bisindolylmaleimide-naphthalimide building block for the construction of the energy transfer cassette.

    Science.gov (United States)

    Li, Xiaochuan; Shi, Ruijuan; Jin, Yingchun; Lou, Yan; Ge, Qingshan; Li, Mengmeng; Kim, Hyungjoo; Son, Young-A

    2014-10-01

    Double build-in chromophores with naphthalimide and bisindolylmaleimide incorporating to one molecule were synthesized efficiently and characterized fully. Its spectral properties were investigated. Effective intramolecular energy transfer together with the strong emission in solution and solid state were discussed in terms of its electronic structures. Optimized structure and frontier molecular orbital were calculated based on D3(mol) platform. Obviously electron delocalization before and after excitation was observed according to the molecular orbital calculation, which corresponds to the mechanism of excitation energy transfer through space occurred in the donor-linker-acceptor molecular system. The opto-physical properties of the dye indicated potential application of electro-optical materials.

  11. The contributions of 49ers to the measurements and models of ultrafast photosynthetic energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, Graham R. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-02-28

    Progress in measuring and understanding the mechanism of the elementary energy transfer steps in photosynthetic light harvesting from roughly 1949 to the present is sketched with a focus on the group of scientists born in 1949 ± 1. Improvements in structural knowledge, laser spectroscopic methods, and quantum dynamical theories have led to the ability to record and calculate with reasonable accuracy the timescales of elementary energy transfer steps. The importance of delocalized excited states and of near-field Coulombic coupling is noted. The microscopic understanding enables consistent coarse graining and should enable a much-improved understanding of the regulation of photosynthetic light harvesting.

  12. The contributions of 49ers to the measurements and models of ultrafast photosynthetic energy transfer.

    Science.gov (United States)

    Fleming, Graham R

    2018-03-01

    Progress in measuring and understanding the mechanism of the elementary energy transfer steps in photosynthetic light harvesting from roughly 1949 to the present is sketched with a focus on the group of scientists born in 1949 ± 1. Improvements in structural knowledge, laser spectroscopic methods, and quantum dynamical theories have led to the ability to record and calculate with reasonable accuracy the timescales of elementary energy transfer steps. The significance of delocalized excited states and of near-field Coulombic coupling is noted. The microscopic understanding enables consistent coarse graining and should enable a much-improved understanding of the regulation of photosynthetic light harvesting.

  13. Rapid and high throughput fabrication of high temperature stable structures through PDMS transfer printing

    Science.gov (United States)

    Hohenberger, Erik; Freitag, Nathan; Korampally, Venumadhav

    2017-07-01

    We report on a facile and low cost fabrication approach for structures—gratings and enclosed nanochannels, through simple solution processed chemistries in conjunction with nanotransfer printing techniques. The ink formulation primarily consisting of an organosilicate polymeric network with a small percentage of added 3-aminopropyl triethoxysilane crosslinker allows one to obtain robust structures that are not only stable towards high temperature processing steps as high as 550 °C but also exhibit exceptional stability against a host of organic solvent washes. No discernable structure distortion was observed compared to the as-printed structures (room temperature processed) when printed structures were subjected to temperatures as high as 550 °C. We further demonstrate the applicability of this technique towards the fabrication of more complex nanostructures such as enclosed channels through a double transfer method, leveraging the exceptional room temperature cross-linking ability of the printed structures and their subsequent resistance to dissolution in organic solvent washes. The exceptional temperature and physico-chemical stability of the nanotransfer printed structures makes this a useful fabrication tool that may be applied as is, or integrated with conventional lithographic techniques for the large area fabrication of functional nanostructures and devices.

  14. Rapid multicomponent relaxometry in steady state with correction of magnetization transfer effects.

    Science.gov (United States)

    Liu, Fang; Block, Walter F; Kijowski, Richard; Samsonov, Alexey

    2016-04-01

    To study the effects of magnetization transfer (MT) on multicomponent T2 parameters obtained using mcDESPOT in macromolecule-rich tissues and to propose a new method called mcRISE to correct MT-induced biases. The two-pool mcDESPOT model was modified by the addition of an exchanging macromolecule proton pool to model the MT effect in cartilage. The mcRISE acquisition scheme was developed to provide sensitivity to all pools. An incremental fitting was applied to estimate MT and relaxometry parameters with minimized coupling. The interaction between MT and relaxometry parameters, efficacy of MT correction, and feasibility of mcRISE in vivo were investigated in simulations and in healthy volunteers. The MT effect caused significant errors in multicomponent T1/T2 values and in fast-relaxing water fraction fF , which is consistent with previous experimental observations. fF increased significantly with macromolecule content if MT was ignored. mcRISE resulted in a multifold reduction of MT biases and yielded decoupled multicomponent T1/T2 relaxometry and quantitative MT parameters. mcRISE is an efficient approach for correcting MT biases in multicomponent relaxometry based on steady state sequences. Improved specificity of mcRISE may help to elucidate the sources of the previously described high sensitivity of noncorrected mcDESPOT parameters to disease-related changes in cartilage and the brain. © 2015 Wiley Periodicals, Inc.

  15. 77 FR 73654 - Eau Galle Renewable Energy Company, Eau Galle Hydro, LLC; Notice of Transfer of Exemption

    Science.gov (United States)

    2012-12-11

    ...] Eau Galle Renewable Energy Company, Eau Galle Hydro, LLC; Notice of Transfer of Exemption 1. By letter filed October 12, 2012, Eau Galle Renewable Energy Company informed the Commission that its exemption..., 1987,\\1\\ and transferred to Eau Galle Renewable Energy Company by letter.\\2\\ The project is located on...

  16. Dynamics of Energy Transfer in a Conjugated Dendrimer Driven by Ultrafast Localization of Excitations.

    Science.gov (United States)

    Galindo, Johan F; Atas, Evrim; Altan, Aysun; Kuroda, Daniel G; Fernandez-Alberti, Sebastian; Tretiak, Sergei; Roitberg, Adrian E; Kleiman, Valeria D

    2015-09-16

    Solar energy conversion starts with the harvest of light, and its efficacy depends on the spatial transfer of the light energy to where it can be transduced into other forms of energy. Harnessing solar power as a clean energy source requires the continuous development of new synthetic materials that can harvest photon energy and transport it without significant losses. With chemically-controlled branched architectures, dendrimers are ideally suited for these initial steps, since they consist of arrays of chromophores with relative positioning and orientations to create energy gradients and to spatially focus excitation energies. The spatial localization of the energy delimits its efficacy and has been a point of intense research for synthetic light harvesters. We present the results of a combined theoretical experimental study elucidating ultrafast, unidirectional, electronic energy transfer on a complex molecule designed to spatially focus the initial excitation onto an energy sink. The study explores the complex interplay between atomic motions, excited-state populations, and localization/delocalization of excitations. Our findings show that the electronic energy-transfer mechanism involves the ultrafast collapse of the photoexcited wave function due to nonadiabatic electronic transitions. The localization of the wave function is driven by the efficient coupling to high-frequency vibrational modes leading to ultrafast excited-state dynamics and unidirectional efficient energy funneling. This work provides a long-awaited consistent experiment-theoretical description of excited-state dynamics in organic conjugated dendrimers with atomistic resolution, a phenomenon expected to universally appear in a variety of synthetic conjugated materials.

  17. Multinucleon transfer dynamics in heavy-ion collisions near Coulomb-barrier energies

    Science.gov (United States)

    Niu, Fei; Chen, Peng-Hui; Guo, Ya-Fei; Ma, Chun-Wang; Feng, Zhao-Qing

    2017-12-01

    Multinucleon transfer reactions near barrier energies have been investigated with a multistep model based on the dinuclear system (DNS) concept, in which the capture of two colliding nuclei, the transfer dynamics, and the deexcitation process of primary fragments are described by an analytical formula, diffusion theory, and a statistical model, respectively. The nucleon transfer takes place after forming the DNS and is coupled to the dissipation of relative motion energy and angular momentum by solving a set of microscopically derived master equations within the potential energy surface. Specific reactions of Ca,4840+124Sn , 40Ca(40Ar,58Ni)+232Th , 40Ca(58Ni)+238U , and Ca,4840(58Ni)+248Cm near barrier energies are investigated. It is found that fragments are produced by multinucleon transfer reactions with maximal yields along the β -stability line. The isospin relaxation is particularly significant in the process of fragment formation. The incident energy dependence of heavy target-like fragments in the reaction of 58Ni+248Cm is analyzed thoroughly.

  18. Surface energy equation for heat transfer process in a pebble fuel

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa-Paredes, G., E-mail: gepe@xanum.uam.mx [Área de Ingeniería en Recursos Energéticos, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186 Col. Vicentina, México, DF 09340 (Mexico); Castillo-Jiménez, V. [Área de Ingeniería en Recursos Energéticos, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186 Col. Vicentina, México, DF 09340 (Mexico); Herranz-Puebla, L.E. [División de Fisión Nuclear, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Avda. Complutense, 22, 28040 Madrid (Spain); Vázquez-Rodríguez, R. [Área de Ingeniería en Recursos Energéticos, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186 Col. Vicentina, México, DF 09340 (Mexico)

    2014-12-15

    Highlights: • Steady and transient behaviors of the interfacial heat transfer in a fuel element. • Non-local averaging volume method for deriving the surface energy equation. • The method captures significant physical phenomena of the interfacial heat transfer. • Closure relationships are proposed in order to obtain the temperatures distribution. • The derived average equation represents an upscaling regarding the local description. - Abstract: In this paper the surface energy equation for the heat transfer process (HT) between the mixture of fuel (TRISO particles and graphite matrix) and coating in a fuel pebble is derived. The fuel pebble can be treated as a heterogeneous region (mixture of microspheres and graphite) interacting thermally with the homogeneous region (the coating or cladding). These two regions are separated by a boundary region where the properties and behavior differ from those of the adjoining regions. The methodology applied for deriving the surface energy equation is based on the classical theory on interfacial transport phenomena. The surface energy equation derived in this work is an average equation that represents an upscaling respect to the local description. The regions around the surface where changes in the physical phenomena are important are of the order of microns, in contrast with interfacial mass transfer between phases that may be several molecular diameters. The numerical analysis regarding the application of surface energy equation is presented in this work.

  19. Imaging charge and energy transfer in molecules using free-electron lasers

    Science.gov (United States)

    Rudenko, Artem

    2014-05-01

    Charge and energy transfer reactions drive numerous important processes in physics, chemistry and biology, with applications ranging from X-ray astrophysics to artificial photosynthesis and molecular electronics. Experimentally, the central goal in studies of transfer phenomena is to trace the spatial localization of charge at a given time. Because of their element and site sensitivity, ultrafast X-rays provide a promising tool to address this goal. In this talk I will discuss several experiments where free-electron lasers were employed to study charge and energy transfer dynamics in fragmenting molecules. In a first example, we used intense, 70 femtosecond 1.5 keV pulses from the Linac Coherent Light Source (LCLS) to study distance dependence of electron transfer in laser-dissociated methyl iodide molecules. Inducing well-localized positive charge on the heavy iodine atom, we observe signature of electron transition from the separated methyl group up to the distances of 35 atomic units. In a complementary experiment, we studied charge exchange between two partners in a dissociating molecular iodine employing a pump-probe arrangement with two identical 90 eV pulses from the Free-Electron LASer in Hamburg (FLASH). In both cases, the effective spatial range of the electron transfer can be reasonably described by a classical over-the-barrier model developed for ion-atom collisions. Finally, I will discuss a time-resolved measurement on non-local relaxation mechanism based on a long-range energy transfer, the so-called interatomic Coulombic decay. This work was supported by Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, US Department of Energy and by the Kansas NSF ``First Award'' program.

  20. Comparing Ray-Based and Wave-Based Models of Cross-Beam Energy Transfer

    Science.gov (United States)

    Follett, R. K.; Edgell, D. H.; Shaw, J. G.; Froula, D. H.; Myatt, J. F.

    2016-10-01

    Ray-based models of cross-beam energy transfer (CBET) are used in radiation-hydrodynamics codes to calculate laser-energy deposition. The accuracy of ray-based CBET models is limited by assumptions about the polarization and phase of the interacting laser beams and by the use of a paraxial Wentzel-Kramers-Brillouin (WKB) approximation. A 3-D wave-based solver (LPSE-CBET) is used to study the nonlinear interaction between overlapping laser beams in underdense plasma. A ray-based CBET model is compared to the wave-based model and shows good agreement in simple geometries where the assumptions of the ray-based model are satisfied. Near caustic surfaces, the assumptions of the ray-based model break down and the calculated energy transfer deviates from wave-based calculations. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  1. Study of energy transfer between molecules placed in the vicinity of a bimetal composite nanoparticle

    Energy Technology Data Exchange (ETDEWEB)

    Daneshfar, Nader, E-mail: ndaneshfar@gmail.com, E-mail: ndaneshfar@razi.ac.ir [Department of Physics, Razi University, Kermanshah (Iran, Islamic Republic of)

    2015-10-15

    In this study, the problem of energy transfer between two molecules near a bimetallic composite nanoparticle is investigated. The influence of the interaction between metal particles on the intermolecular energy is studied, because when two metal nanoparticles are placed close to each other, their plasmons coupling giving rise to new features. On the other hand, we discuss the transfer of resonance energy between donor and acceptor molecules (a single donor and a single acceptor) in the presence of a nanocomposite containing gold and silver nanoparticles based on the Maxwell-Garnett effective medium theory and within the quasistatic limit. We show that the interaction energy strongly depends on the particle size, the filling factor of metal particles, the intermolecular distance (the distance between the donor and acceptor molecules), and the dielectric constant of host matrix.

  2. Nature does not rely on long-lived electronic quantum coherence for photosynthetic energy transfer

    CERN Document Server

    Duan, Hong-Guang; Cogdell, Richard; Ashraf, Khuram; Stevens, Amy L; Thorwart, Michael; Miller, R J Dwayne

    2016-01-01

    During the first steps of photosynthesis, the energy of impinging solar photons is transformed into electronic excitation energy of the light-harvesting biomolecular complexes. The subsequent energy transfer to the reaction center is understood in terms of exciton quasiparticles which move on a grid of biomolecular sites on typical time scales less than 100 femtoseconds (fs). Since the early days of quantum mechanics, this energy transfer is described as an incoherent Forster hopping with classical site occupation probabilities, but with quantum mechanically determined rate constants. This orthodox picture has been challenged by ultrafast optical spectroscopy experiments with the Fenna-Matthews-Olson protein in which interference oscillatory signals up to 1.5 picoseconds were reported and interpreted as direct evidence of exceptionally long-lived electronic quantum coherence. Here, we show that the optical 2D photon echo spectra of this complex at ambient temperature in aqueous solution do not provide evidenc...

  3. Nonhelical turbulence and the inverse transfer of energy: A parameter study

    Science.gov (United States)

    Reppin, Johannes; Banerjee, Robi

    2017-11-01

    We explore the phenomenon of the recently discovered inverse transfer of energy from small to large scales in decaying magnetohydrodynamical turbulence by Brandenburg et al. [Phys. Rev. Lett. 114, 075001 (2015), 10.1103/PhysRevLett.114.075001], even for nonhelical magnetic fields. For this investigation we mainly employ the Pencil Code performing a parameter study, where we vary the Prandtl number, the kinematic viscosity, and the initial spectrum. We find that to get a decay that exhibits this inverse transfer, large Reynolds numbers (O ˜103 ) are needed and low Prandtl numbers of the order unity Pr=1 are preferred. Compared to helical MHD turbulence, though, the inverse transfer is much less efficient in transferring magnetic energy to larger scales than the well-known effect of the inverse cascade. Hence, applying the inverse transfer to the magnetic field evolution in the Early Universe, we question whether the nonhelical inverse transfer is effective enough to explain the observed void magnetic fields if a magnetogenesis scenario during the electroweak phase transition is assumed.

  4. Fast low-energy halo-to-halo transfers between Sun–planet systems

    Directory of Open Access Journals (Sweden)

    Shang Haibin

    2014-04-01

    Full Text Available In this paper, the problem of fast low-energy halo-to-halo transfers between Sun–planet systems is discussed under ephemeris constraints. According to the structure of an invariant manifold, employing an invariant manifold and planetary gravity assist to save fuel consumption is analyzed from the view of orbital energy. Then, a pseudo-manifold is introduced to replace the invariant manifold in such a way that more transfer opportunities are allowed. Fast escape and capture can be achieved along the pseudo-manifold. Furthermore, a global searching method that is based on patched-models is proposed to find an appropriate transfer trajectory. In this searching method, the trajectory is divided into several segments that can be designed under simple dynamical models, and an analytical algorithm is developed for connecting the segments. Earth–Mars and Earth–Venus halo-to-halo transfers are designed to demonstrate the proposed approach. Numerical results show that the transfers that combine the pseudo-manifolds and planetary gravity assist can offer significant fuel consumption and flight time savings over traditional transfer schemes.

  5. Experimental and theoretical investigations of rotational energy transfer in HBr + He collisions.

    Science.gov (United States)

    Kabir, Md Humayun; Antonov, Ivan O; Merritt, Jeremy M; Heaven, Michael C

    2010-10-28

    Rotational relaxation rates for HBr(v = 1) colliding with helium atoms at room temperature have been measured using a time-resolved optical-optical double resonance technique. Rotational state selective excitation of v = 1 for rotational levels in the range J = 1-9 was achieved by stimulated Raman pumping. The population decay in the prepared states and the transfer of population to nearby rotational states was monitored via 2 + 1 resonance-enhanced multiphoton ionization (REMPI) spectroscopy using the g(3)Σ(-)-X(1)Σ(+) (0-1) band. Collision-induced population evolution for transfer events with |ΔJ| ≤ 8 was observed at pressures near 0.7 Torr. The experimental data were analyzed using fitting and scaling functions to generate state-to-state rotational energy transfer rate constant matrices. Total depopulation rate constants were found to be in the range (1.3 to 2.0) × 10(-10) cm(3) s(-1). As a test of current computational methods, state-to-state rotational energy transfer rate constants were calculated using ab initio theory. The total removal rate constants were in good agreement with the measured values, but the transfer probabilities for events with |ΔJ| ≥ 3 were underestimated. Inspection of the anisotropic characteristics of the potential energy surface did not yield an obvious explanation for the discrepancies, but it is most likely that the problem stems from inaccuracies in the potential surface.

  6. Energy transfer mechanism and optoelectronic properties of (PFO/TiO2)/Fluorol 7GA nanocomposite thin films

    Science.gov (United States)

    Al-Asbahi, Bandar Ali

    2017-10-01

    Energy transfer between poly (9,9'-di-n-octylfluorenyl-2,7-diyl) (PFO) as a donor in presence of TiO2 nanoparticles (NPs) and Fluorol 7GA as an acceptor with different weight ratios has been investigated by steady-state emission measurements. Based on the absorption and fluorescence measurements, the energy transfer properties, such as quenching rate constant (kSV), energy transfer rate constant (kET), quantum yield (ϕDA), and lifetime (τDA), of the donor in the presence of the acceptor, energy transfer probability (PDA), energy transfer efficiency (η), energy transfer time (τET), and critical distance of the energy transfer (Ro) were calculated. Förster-type energy transfer between the excited donor and ground-state acceptor molecules was the dominant mechanism responsible for the energy transfer as evidenced by large values of kSV, kET, and Ro. Moreover, these composite materials were employed as an emissive layer in organic light-emitting diodes (OLEDs). Additionally, the optoelectronic properties of OLEDs were investigated in terms of current density-voltage characteristics and electroluminescence spectra.

  7. Energy transfer cassettes based on organic fluorophores: construction and applications in ratiometric sensing.

    Science.gov (United States)

    Fan, Jiangli; Hu, Mingming; Zhan, Peng; Peng, Xiaojun

    2013-01-07

    This tutorial review presents some recent developments in the construction and applications of cassettes based on resonance energy transfer between fluorescent dyes in the visible and infrared region. We focused on the contributions of different connections between the energy donor and acceptor according to the "through-space" and "through-bond" methods, and emphasised their applications in ratiometric sensing for the detection of ions and small molecules.

  8. 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

  9. Picosecond excitation energy transfer of allophycocyanin studied in solution and in crystals.

    Science.gov (United States)

    Ranjbar Choubeh, Reza; Sonani, Ravi R; Madamwar, Datta; Struik, Paul C; Bader, Arjen N; Robert, Bruno; van Amerongen, Herbert

    2018-03-01

    Cyanobacteria perform photosynthesis with the use of large light-harvesting antennae called phycobilisomes (PBSs). These hemispherical PBSs contain hundreds of open-chain tetrapyrrole chromophores bound to different peptides, providing an arrangement in which excitation energy is funnelled towards the PBS core from where it can be transferred to photosystem I and/or photosystem II. In the PBS core, many allophycocyanin (APC) trimers are present, red-light-absorbing phycobiliproteins that covalently bind phycocyanobilin (PCB) chromophores. APC trimers were amongst the first light-harvesting complexes to be crystallized. APC trimers have two spectrally different PCBs per monomer, a high- and a low-energy pigment. The crystal structure of the APC trimer reveals the close distance (~21 Å) between those two chromophores (the distance within one monomer is ~51 Å) and this explains the ultrafast (~1 ps) excitation energy transfer (EET) between them. Both chromophores adopt a somewhat different structure, which is held responsible for their spectral difference. Here we used spectrally resolved picosecond fluorescence to study EET in these APC trimers both in crystallized and in solubilized form. We found that not all closely spaced pigment couples consist of a low- and a high-energy pigment. In ~10% of the cases, a couple consists of two high-energy pigments. EET to a low-energy pigment, which can spectrally be resolved, occurs on a time scale of tens of picoseconds. This transfer turns out to be three times faster in the crystal than in the solution. The spectral characteristics and the time scale of this transfer component are similar to what have been observed in the whole cells of Synechocystis sp. PCC 6803, for which it was ascribed to EET from C-phycocyanin to APC. The present results thus demonstrate that part of this transfer should probably also be ascribed to EET within APC trimers.

  10. Theoretical Analysis for Heat Transfer Optimization in Subcritical Electrothermal Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Peng Hu

    2017-02-01

    Full Text Available Electrothermal energy storage (ETES provides bulk electricity storage based on heat pump and heat engine technologies. A subcritical ETES is described in this paper. Based on the extremum principle of entransy dissipation, a geometry model is developed for heat transfer optimization for subcritical ETES. The exergy during the heat transfer process is deduced in terms of entropy production. The geometry model is validated by the extremum principle of entropy production. The theoretical analysis results show that the extremum principle of entransy dissipation is an effective criterion for the optimization, and the optimum heat transfer for different cases with the same mass flux or pressure has been discussed. The optimum heat transfer can be achieved by adjusting the mass flux and pressure of the working fluid. It also reveals that with the increase of mass flux, there is a minimum exergy in the range under consideration, and the exergy decreases with the increase of the pressure.

  11. HOMO energy gap dependence of hole-transfer kinetics in DNA.

    Science.gov (United States)

    Kawai, Kiyohiko; Hayashi, Mitsuo; Majima, Tetsuro

    2012-03-14

    DNA consists of two type of base-pairs, G-C and A-T, in which the highest occupied molecular orbital (HOMO) localizes on the purine bases G and A. While the hole transfer through consecutive Gs or As occurs faster than 10(9) s(-1), a significant drop in the hole transfer rate was observed for G-C and A-T mixed random sequences. In this study, by using various natural and artificial nucleobases having different HOMO levels, the effect of the HOMO-energy gap between bases (Δ(HOMO)) on the hole-transfer kinetics in DNA was investigated. The results demonstrated that the hole transfer rate can be increased by decreasing the Δ(HOMO) and can be finely tuned over 3 orders of magnitude by varying the Δ(HOMO).

  12. Energy conservation via heat transfer enhancement. Quarterly progress report, January 1-March 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Bergles, A.E.; Junkhan, G.H.; Webb, R.L.

    1979-06-01

    This report for the first quarter of 1979 summarizes visits and contacts relative to the theory and practice of heat transfer enhancement. The Technical Literature File and Manufacturers' File were expanded, and the initial Patent Technology Information File was completed. Application studies on enhancement of waste heat recuperators and laminar internal flow heat transfer are described. A comprehensive bibliography on laminar flow enhancement is included. The Technology study on performance of internally finned tubes is complete. New data for the heat transfer and friction characteristics of internally finned tubes will be analyzed to develop rationally based correlations. An assessment of natural convection from rough surfaces was performed. Major effort was directed toward planning of the Research Workshop on Energy Conservation Through Enhanced Heat Transfer. The Workshop, scheduled for May 24 and May 25, 1979 in Chicago, will be co-sponsored by NSF.

  13. 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.

  14. Temperature dependence of energy transfer mechanisms in Eu-doped GaN

    Science.gov (United States)

    Lee, Chang-Won; Everitt, Henry O.; Lee, D. S.; Steckl, A. J.; Zavada, J. M.

    2004-06-01

    The temperature dependent behavior of continuous-wave and time-resolved photoluminescence of Eu-doped GaN in the visible region is measured for both the 5D0→7F2 and 5D0→7F3 transitions. The radiative decay of these transitions, following pulsed laser excitation of the GaN host, is monitored by a grating spectrometer and photomultiplier tube detector system. In addition to these two radiative energy transfer pathways within Eu3+, the data reveal two nonradiative energy transfer paths between Eu3+ and the host GaN. Decay constants for the relaxation processes are extracted from the data using a numerically solved rate equation model. Although the dominant radiative relaxation processes decayed with a temperature insensitive decay constant of 166 μs, a prominent role for nonradiative transfer between Eu3+ and impurities within the GaN host was deduced above 180 K.

  15. 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.

  16. 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.

  17. Migration-assisted energy transfer at conjugated polymer/metal interfaces

    NARCIS (Netherlands)

    Markov, DE; Blom, PWM

    2005-01-01

    The dynamics of exciton quenching in a conjugated polymer due to the presence of metal films is analyzed using time-resolved photoluminescence. The quenching is governed by direct radiationless energy transfer to the metal and is further enhanced by diffusion of excitons into the depletion area of

  18. A new energy transfer channel from carotenoids to chlorophylls in purple bacteria.

    Science.gov (United States)

    Feng, Jin; Tseng, Chi-Wei; Chen, Tingwei; Leng, Xia; Yin, Huabing; Cheng, Yuan-Chung; Rohlfing, Michael; Ma, Yuchen

    2017-07-10

    It is unclear whether there is an intermediate dark state between the S 2 and S 1 states of carotenoids. Previous two-dimensional electronic spectroscopy measurements support its existence and its involvement in the energy transfer from carotenoids to chlorophylls, but there is still considerable debate on the origin of this dark state and how it regulates the energy transfer process. Here we use ab initio calculations on excited-state dynamics and simulated two-dimensional electronic spectrum of carotenoids from purple bacteria to provide evidence supporting that the dark state may be assigned to a new A g + state. Our calculations also indicate that groups on the conjugation backbone of carotenoids may substantially affect the excited-state levels and the energy transfer process. These results contribute to a better understanding of carotenoid excited states.Carotenoids harvest energy from light and transfer it to chlorophylls during photosynthesis. Here, Feng et al. perform ab initio calculations on excited-state dynamics and simulated 2D electronic spectrum of carotenoids, supporting the existence of a new excited state in carotenoids.

  19. 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

  20. Combustion and Energy Transfer Experiments: A Laboratory Model for Linking Core Concepts across the Science Curriculum

    Science.gov (United States)

    Barreto, Jose C.; Dubetz, Terry A.; Schmidt, Diane L.; Isern, Sharon; Beatty, Thomas; Brown, David W.; Gillman, Edward; Alberte, Randall S.; Egiebor, Nosa O.

    2007-01-01

    Core concepts can be integrated throughout lower-division science and engineering courses by using a series of related, cross-referenced laboratory experiments. Starting with butane combustion in chemistry, the authors expanded the underlying core concepts of energy transfer into laboratories designed for biology, physics, and engineering. This…

  1. Scaling Relations and Optimization of Excitonic Energy Transfer Rates between One-Dimensional Molecular Aggregates

    NARCIS (Netherlands)

    Chuang, Chern; Knoester, Jasper; Cao, Jianshu

    2014-01-01

    We theoretically study the distance, chain length, and temperature dependence of the electronic couplings as well as the excitonic energy transfer rates between one-dimensional (1D) chromophore aggregates. In addition to the well-known geometry dependent factor that leads to the deviation from

  2. Energy transfer, volumetric expansion, and removal of oral biofilms by non-contact brushing

    NARCIS (Netherlands)

    Busscher, H. J.; Jager, D.; Finger, G.; Schaefer, N.; van der Mei, H. C.

    Non-contact removal of oral biofilms offers advantages beyond the reach of bristles, but it is unknown how energy transfer for removal from brush-to-biofilm occurs. In the present study we evaluated non-contact, oral biofilm removal by oscillating-rotating and sonic toothbrushes, and their acoustic

  3. 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.

  4. "Super-Reducing" Photocatalysis: Consecutive Energy and Electron Transfers with Polycyclic Aromatic Hydrocarbons.

    Science.gov (United States)

    Brasholz, Malte

    2017-08-21

    Donation welcome: Recent developments in visible-light photocatalysis allow the utilization of increasingly negative reduction potentials. Successive energy and electron transfer with polycyclic aromatic hydrocarbons enables the catalytic formation of strongly reducing arene radical anions, classical stoichiometric reagents for one-electron reduction in organic synthesis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. 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...

  6. Determining excitation-energy transfer times and mechanisms from stochastic time-dependent density functional theory.

    Science.gov (United States)

    Hofmann-Mees, D; Appel, H; Di Ventra, M; Kümmel, S

    2013-11-21

    We developed an approach for calculating excitation-energy transfer times in supermolecular arrangements based on stochastic time-dependent density functional theory (STDDFT). The combination of real-time propagation and the stochastic Schrödinger equation with a Kohn-Sham Hamiltonian allows for simulating how an excitation spreads through an assembly of molecular systems. The influence that approximations, such as the dipole-dipole coupling approximation of Förster theory, have on energy-transfer times can be checked explicitly. As a first application of our approach we investigate a light-harvesting-inspired model ring system, calculating the time it takes for an excitation to travel from one side of the ring to the opposite side under ideal and perturbed conditions. Among other things we find that completely removing a molecule from the ring may inhibit energy transfer less than having an energetically detuned molecule in the ring. In addition, Förster's dipole coupling approximation may noticeably overestimate excitation-energy transfer efficiency.

  7. Energy transfer and biexciton decay in Cs2UO2Cl4 crystals

    NARCIS (Netherlands)

    Krol, D.M.

    1980-01-01

    We have investigated the influence of energy transfer on luminescence properties of Cs2UO2Cl4 crystals at low temperatures. Time-resolved emission spectra and luminescence decay times were measured between 1.5 and 15 K with the use of selective excitation techniques. The luminescence of Cs2UO2Cl4

  8. Efficient Energy Transfer in Supramolecular, Hydrogen-Bonded Polypyridylruthenium-Osmium Complexes

    NARCIS (Netherlands)

    Rau, Sven; Schäfer, Bernhard; Schebesta, Sebastian; Grüßing, André; Poppitz, Wolfgang; Walther, Dirk; Duati, Marco; Browne, Wesley R.; Vos, Johannes G.

    Hydrogen bond association between ruthenium bibenzimidazole and carboxylated polypyridylosmium complexes results in stable supramolecular aggregates. The determined stability constant of logK approximate to 6 +/- 0.3 allows efficient energy transfer from the ruthenium to the osmium moiety. (C)

  9. Porphyrin nanorods characterisation for an artificial light harvesting and energy transfer system

    CSIR Research Space (South Africa)

    Mongwaketsi, N

    2010-01-01

    Full Text Available s 1 0 h r s 1 3 h r s 1 5 h r s 1 8 h r s Porphyrin Nanorods Characterization for an Artificial Light Harvesting and Energy Transfer System Nametso Mongwaketsi1,2,3, Raymond Sparrow2, Bert Klumperman3, Malik Maaza1 1 NanoSciences Lab...

  10. Grid to vehicle and vehicle to grid energy transfer using single ...

    African Journals Online (AJOL)

    user

    converter based energy transfer from electrical vehicle to grid(V2G) and grid to vehicle .... used in application requiring high DC bus voltage such as UPS systems, a line .... MATLAB/simulink using a model given in (Massimo et at al., 2000).

  11. Proton transfer pathways, energy landscape, and kinetics in creatine-water systems.

    Science.gov (United States)

    Ivchenko, Olga; Whittleston, Chris S; Carr, Joanne M; Imhof, Petra; Goerke, Steffen; Bachert, Peter; Wales, David J

    2014-02-27

    We study the exchange processes of the metabolite creatine, which is present in both tumorous and normal tissues and has NH2 and NH groups that can transfer protons to water. Creatine produces chemical exchange saturation transfer (CEST) contrast in magnetic resonance imaging (MRI). The proton transfer pathway from zwitterionic creatine to water is examined using a kinetic transition network constructed from the discrete path sampling approach and an approximate quantum-chemical energy function, employing the self-consistent-charge density-functional tight-binding (SCC-DFTB) method. The resulting potential energy surface is visualized by constructing disconnectivity graphs. The energy landscape consists of two distinct regions corresponding to the zwitterionic creatine structures and deprotonated creatine. The activation energy that characterizes the proton transfer from the creatine NH2 group to water was determined from an Arrhenius fit of rate constants as a function of temperature, obtained from harmonic transition state theory. The result is in reasonable agreement with values obtained in water exchange spectroscopy (WEX) experiments.

  12. Photoinduced energy and charge transfer in layered porphyrin-gold nanoparticle thin films

    NARCIS (Netherlands)

    Kotiaho, Anne; Lahtinen, Riikka; Lehtivuori, Heli; Tkachenko, Nikolai V.; Lemmetyinen, Helge

    2008-01-01

    In thin films of porphyrin (H2P) and gold nanoparticles (AuNPs), photoexcitation of porphyrins leads to energy and charge transfer to the gold nanoparticles. Alternating layers of porphyrins and octanethiol protected gold nanoparticles (dcore ∼3 nm) were deposited on solid substrates via the

  13. 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

  14. Cascaded plasmon-plasmon coupling mediated energy transfer across stratified metal-dielectric nanostructures.

    Science.gov (United States)

    Golmakaniyoon, Sepideh; Hernandez-Martinez, Pedro Ludwig; Demir, Hilmi Volkan; Sun, Xiao Wei

    2016-10-04

    Surface plasmon (SP) coupling has been successfully applied to nonradiative energy transfer via exciton-plasmon-exciton coupling in conventionally sandwiched donor-metal film-acceptor configurations. However, these structures lack the desired efficiency and suffer poor photoemission due to the high energy loss. Here, we show that the cascaded exciton-plasmon-plasmon-exciton coupling in stratified architecture enables an efficient energy transfer mechanism. The overlaps of the surface plasmon modes at the metal-dielectric and dielectric-metal interfaces allow for strong cross-coupling in comparison with the single metal film configuration. The proposed architecture has been demonstrated through the analytical modeling and numerical simulation of an oscillating dipole near the stratified nanostructure of metal-dielectric-metal-acceptor. Consistent with theoretical and numerical results, experimental measurements confirm at least 50% plasmon resonance energy transfer enhancement in the donor-metal-dielectric-metal-acceptor compared to the donor-metal-acceptor structure. Cascaded plasmon-plasmon coupling enables record high efficiency for exciton transfer through metallic structures.

  15. 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.

  16. 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

  17. 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....

  18. 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

  19. Elastic, excitation, ionization and charge transfer cross sections of current interest in fusion energy research

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, D.R.; Krstic, P.S. [Oak Ridge National Lab. TN (United States). Physics Div.

    1997-01-01

    Due to the present interest in modeling and diagnosing the edge and divertor plasma regions in magnetically confined fusion devices, we have sought to provide new calculations regarding the elastic, excitation, ionization, and charge transfer cross sections in collisions among relevant ions, neutrals, and isotopes in the low-to intermediate-energy regime. We summarize here some of our recent work. (author)

  20. Interplay between Static and Dynamic Energy Transfer in Biofunctional Upconversion Nanoplatforms

    NARCIS (Netherlands)

    Ding, Yadan; Wu, Fei; Zhang, Youlin; Liu, Xiaomin; de Jong, Elinore M. L. D.; Gregorkiewicz, Tom; Hong, Xia; Liu, Yichun; Aalders, Maurice C. G.; Buma, Wybren Jan; Zhang, Hong

    2015-01-01

    Clarification of the energy-transfer (ET) mechanism is of vital importance for constructing efficient upconversion nanoplatforms for biological/biomedical applications. Yet, most strategies of optimizing these nanoplatforms were casually based on a dynamic ET assumption. In this work, we have

  1. 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.

  2. Direct measurement of the kinetics of CBM9 fusion-tag bioprocessing using luminescence resonance energy transfer.

    Science.gov (United States)

    Kavoosi, Mojgan; Creagh, A Louise; Turner, Robin F B; Kilburn, Douglas G; Haynes, Charles A

    2009-01-01

    The economics of affinity-tagging technologies, particularly at preparative scales, depends in part on the cost and efficiency of the bioprocessing step used to remove the affinity tag and obtain the final purified product (Lowe et al., J Biochem Biophys Methods. 2001;49:561-574). When CBM9, the family 9 cellulose binding module from Thermotoga maritima, serves as the affinity tag, the overall efficiency of tag removal is a function of the choice of processing enzyme and the local structure of the cleavage site, most notably the linker sequence flanking the bioprocessing recognition site on the tag side. A novel spectroscopic method is reported and used to rapidly and accurately measure CBM9 fusion-tag bioprocessing kinetics and their dependence on the choice of linker sequence. The assay monitors energy transfer between a lanthanide-based donor bound to the CBM9 tag and an acceptor fluorophore presented on the target protein or peptide. Enzyme-catalyzed cleavage of the fusion tag terminates this resonance energy transfer, resulting in a change in fluorescence intensity that can be monitored to quantify substrate concentration over time. The assay is simple, fast and accurate, providing k(cat)/K(M) values that contain standard errors of less than 3%. As a result, both substantial and subtle differences in bioprocessing kinetics can be measured and used to guide bioproduct design. 2009 American Institute of Chemical Engineers

  3. 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.

  4. On the Statistical Properties of Turbulent Energy Transfer Rate in the Inner Heliosphere

    Science.gov (United States)

    Sorriso-Valvo, Luca; Carbone, Francesco; Perri, Silvia; Greco, Antonella; Marino, Raffaele; Bruno, Roberto

    2018-01-01

    The transfer of energy from large to small scales in solar wind turbulence is an important ingredient of the long-standing question of the mechanism of the interplanetary plasma heating. Previous studies have shown that magnetohydrodynamic (MHD) turbulence is statistically compatible with the observed solar wind heating as it expands in the heliosphere. However, in order to understand which processes contribute to the plasma heating, it is necessary to have a local description of the energy flux across scales. To this aim, it is customary to use indicators such as the magnetic field partial variance of increments (PVI), which is associated with the local, relative, scale-dependent magnetic energy. A more complete evaluation of the energy transfer should also include other terms, related to velocity and cross-helicity. This is achieved here by introducing a proxy for the local, scale-dependent turbulent energy transfer rate ɛ_{Δ t}(t), based on the third-order moment scaling law for MHD turbulence. Data from Helios 2 are used to determine the statistical properties of such a proxy in comparison with the magnetic and velocity fields PVI, and the correlation with local solar wind heating is computed. PVI and ɛ_{Δ t}(t) are generally well correlated; however, ɛ_{Δ t}(t) is a very sensitive proxy that can exhibit large amplitude values, both positive and negative, even for low amplitude peaks in the PVI. Furthermore, ɛ_{Δ t}(t) is very well correlated with local increases of the temperature when large amplitude bursts of energy transfer are localized, thus suggesting an important role played by this proxy in the study of plasma energy dissipation.

  5. Correlation between the Open-Circuit Voltage and Charge Transfer State Energy in Organic Photovoltaic Cells.

    Science.gov (United States)

    Zou, Yunlong; Holmes, Russell J

    2015-08-26

    In order to further improve the performance of organic photovoltaic cells (OPVs), it is essential to better understand the factors that limit the open-circuit voltage (VOC). Previous work has sought to correlate the value of VOC in donor-acceptor (D-A) OPVs to the interface energy level offset (EDA). In this work, measurements of electroluminescence are used to extract the charge transfer (CT) state energy for multiple small molecule D-A pairings. The CT state as measured from electroluminescence is found to show better correlation to the maximum VOC than EDA. The difference between EDA and the CT state energy is attributed to the Coulombic binding energy of the CT state. This correlation is demonstrated explicitly by inserting an insulating spacer layer between the donor and acceptor materials, reducing the binding energy of the CT state and increasing the measured VOC. These results demonstrate a direct correlation between maximum VOC and CT state energy.

  6. Near-field effects and energy transfer in hybrid metal-oxide nanostructures

    Directory of Open Access Journals (Sweden)

    Ulrich Herr

    2013-05-01

    Full Text Available One of the big challenges of the 21st century is the utilization of nanotechnology for energy technology. Nanoscale structures may provide novel functionality, which has been demonstrated most convincingly by successful applications such as dye-sensitized solar cells introduced by M. Grätzel. Applications in energy technology are based on the transfer and conversion of energy. Following the example of photosynthesis, this requires a combination of light harvesting, transfer of energy to a reaction center, and conversion to other forms of energy by charge separation and transfer. This may be achieved by utilizing hybrid nanostructures, which combine metallic and nonmetallic components. Metallic nanostructures can interact strongly with light. Plasmonic excitations of such structures can cause local enhancement of the electrical field, which has been utilized in spectroscopy for many years. On the other hand, the excited states in metallic structures decay over very short lifetimes. Longer lifetimes of excited states occur in nonmetallic nanostructures, which makes them attractive for further energy transfer before recombination or relaxation sets in. Therefore, the combination of metallic nanostructures with nonmetallic materials is of great interest. We report investigations of hybrid nanostructured model systems that consist of a combination of metallic nanoantennas (fabricated by nanosphere lithography, NSL and oxide nanoparticles. The oxide particles were doped with rare-earth (RE ions, which show a large shift between absorption and emission wavelengths, allowing us to investigate the energy-transfer processes in detail. The main focus is on TiO2 nanoparticles doped with Eu3+, since the material is interesting for applications such as the generation of hydrogen by photocatalytic splitting of water molecules. We use high-resolution techniques such as confocal fluorescence microscopy for the investigation of energy-transfer processes. The

  7. Picosecond Energy Transfer and Multiexciton Transfer Outpaces Auger Recombination in Binary CdSe Nano-Platelet Solids

    Energy Technology Data Exchange (ETDEWEB)

    Rowland, Clare E.; Fedin, Igor; Zhang, Hui; Gray, Stephen K.; Govorov, Alexander (Sasha); Talapin, Dimitri V.; Schaller, Richard D.

    2015-05-01

    Fluorescence resonance energy transfer (FRET) enables photosynthetic light harvesting1, wavelength down-conversion in light-emitting diodes (LEDs)2, and optical bio-sensing schemes3. The rate and efficiency of this donor to acceptor transfer of excitation between chromophores dictates the utility of FRET and can unlock new device operation motifs including quantum-funnel solar cells4, non-contact chromophore pumping from a proximal LED5, and drastically reduced gain thresholds6. However, the fastest reported FRET time constants involving spherical quantum dots (QDs) (0.12-1 ns7-9), do not outpace biexciton Auger recombination (0.01-0.1 ns)10, which impedes multiexciton-driven applications including electrically-pumped lasers11 and carrier-multiplication-enhanced photovoltaics.12,13 Few-monolayer thick semiconductor nano-platelets (NPLs) with tens-of-nanometer diameters14 exhibit intense optical transitions14 and hundreds-of-picosecond Auger recombination15,16, but heretofore lack FRET characterizations. We examine binary CdSe NPL solids and show that inter-plate FRET (~6-23 ps, presumably for co-facial arrangements) can occur 15-50 times faster than Auger recombination15,16 and demonstrate multiexcitonic FRET, making such materials ideal candidates for advanced technologies.

  8. Light Absorption and Energy Transfer in the Antenna Complexes of Photosynthetic Organisms.

    Science.gov (United States)

    Mirkovic, Tihana; Ostroumov, Evgeny E; Anna, Jessica M; van Grondelle, Rienk; Govindjee; Scholes, Gregory D

    2017-01-25

    The process of photosynthesis is initiated by the capture of sunlight by a network of light-absorbing molecules (chromophores), which are also responsible for the subsequent funneling of the excitation energy to the reaction centers. Through evolution, genetic drift, and speciation, photosynthetic organisms have discovered many solutions for light harvesting. In this review, we describe the underlying photophysical principles by which this energy is absorbed, as well as the mechanisms of electronic excitation energy transfer (EET). First, optical properties of the individual pigment chromophores present in light-harvesting antenna complexes are introduced, and then we examine the collective behavior of pigment-pigment and pigment-protein interactions. The description of energy transfer, in particular multichromophoric antenna structures, is shown to vary depending on the spatial and energetic landscape, which dictates the relative coupling strength between constituent pigment molecules. In the latter half of the article, we focus on the light-harvesting complexes of purple bacteria as a model to illustrate the present understanding of the synergetic effects leading to EET optimization of light-harvesting antenna systems while exploring the structure and function of the integral chromophores. We end this review with a brief overview of the energy-transfer dynamics and pathways in the light-harvesting antennas of various photosynthetic organisms.

  9. Tryptophan-to-Tryptophan Energy Transfer in UV-B photoreceptor UVR8

    Science.gov (United States)

    Li, Xiankun; Zhong, Dongping

    UVR8 (UV RESISTANCE LOCUS 8) protein is a UV-B photoreceptor in high plants. UVR8 is a homodimer that dissociates into monomers upon UV-B irradiation (280 nm to 315 nm), which triggers various protective mechanisms against UV damages. Uniquely, UVR8 does not contain any external chromophores and utilizes the UV-absorbing natural amino acid tryptophan (Trp) to perceive UV-B. Each UVR8 monomer has 14 tryptophan residues. However, only 2 epicenter Trp (W285 W233) are critical to the light induced dimer-to-monomer transformation. Here, we revealed, using site-directed mutagenesis and spectroscopy, a striking energy flow network, in which other tryptophan chromophores serve as antenna to transfer excitation energy to epicenter Trp, greatly enhancing UVR8 light-harvesting efficiency. Furthermore, Trp-to-Trp energy transfer rates were measured and agree well with theoretical values.

  10. 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

  11. Nonphotochemical Hole-Burning Studies of Energy Transfer Dynamics in Antenna Complexes of Photosynthetic Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Matsuzaki, Satoshi [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    This thesis contains the candidate's original work on excitonic structure and energy transfer dynamics of two bacterial antenna complexes as studied using spectral hole-burning spectroscopy. The general introduction is divided into two chapters (1 and 2). Chapter 1 provides background material on photosynthesis and bacterial antenna complexes with emphasis on the two bacterial antenna systems related to the thesis research. Chapter 2 reviews the underlying principles and mechanism of persistent nonphotochemical hole-burning (NPHB) spectroscopy. Relevant energy transfer theories are also discussed. Chapters 3 and 4 are papers by the candidate that have been published. Chapter 3 describes the application of NPHB spectroscopy to the Fenna-Matthews-Olson (FMO) complex from the green sulfur bacterium Prosthecochloris aestuarii; emphasis is on determination of the low energy vibrational structure that is important for understanding the energy transfer process associated within three lowest energy Qy-states of the complex. The results are compared with those obtained earlier on the FMO complex from Chlorobium tepidum. In Chapter 4, the energy transfer dynamics of the B800 molecules of intact LH2 and B800-deficient LH2 complexes of the purple bacterium Rhodopseudomonas acidophila are compared. New insights on the additional decay channel of the B800 ring of bacteriochlorophylla (BChla) molecules are provided. General conclusions are given in Chapter 5. A version of the hole spectrum simulation program written by the candidate for the FMO complex study (Chapter 3) is included as an appendix. The references for each chapter are given at the end of each chapter.

  12. Energy transfer dynamics in an RC-LH1-PufX tubular photosynthetic membrane

    Science.gov (United States)

    Hsin, J.; Strümpfer, J.; Şener, M.; Qian, P.; Hunter, C. N.; Schulten, K.

    2010-08-01

    Light absorption and the subsequent transfer of excitation energy are the first two steps in the photosynthetic process, carried out by protein-bound pigments, mainly bacteriochlorophylls (BChls), in photosynthetic bacteria. BChls are anchored in light-harvesting (LH) complexes, such as light-harvesting complex I (LH1), which directly associates with the reaction center (RC), forming the RC-LH1 core complex. In Rhodobacter sphaeroides, RC-LH1 core complexes contain an additional protein, PufX, and assemble into dimeric RC-LH1-PufX core complexes. In the absence of LH complex II (LH2), the former complexes can aggregate into a helically ordered tubular photosynthetic membrane. We have examined the excitation transfer dynamics in a single RC-LH1-PufX core complex dimer using the hierarchical equations of motion for dissipative quantum dynamics that accurately, yet in a computationally costly manner, treat the coupling between BChls and their protein environment. A widely employed description, the generalized Förster (GF) theory, was also used to calculate the transfer rates of the same excitonic system in order to verify the accuracy of this computationally cheap method. Additionally, in light of the structural uncertainties in the Rba. sphaeroides RC-LH1-PufX core complex, geometrical alterations were introduced into the BChl organization. It is shown that the energy transfer dynamics are not affected by the considered changes in the BChl organization and that the GF theory provides accurate transfer rates. An all-atom model for a tubular photosynthetic membrane is then constructed on the basis of electron microscopy data, and the overall energy transfer properties of this membrane are computed.

  13. Assessment of quantum chemical methods and basis sets for excitation energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Fink, Reinhold F. [Institute of Physical Chemistry, University of Wuerzburg, Am Hubland, D-97074 Wuerzburg (Germany); Pfister, Johannes; Zhao Hongmei [Institute of Organic Chemistry, University of Wuerzburg, Am Hubland, D-97074 Wuerzburg (Germany); Engels, Bernd [Institute of Organic Chemistry, University of Wuerzburg, Am Hubland, D-97074 Wuerzburg (Germany)], E-mail: bernd@chemie.uni-wuerzburg.de

    2008-05-04

    The validity of several standard quantum chemical approaches and other models for the prediction of exciton energy transfer is investigated using the HOMO-LUMO excited states of benzene dimer as an example. The configuration interaction singles (CIS), time-dependent Hartree-Fock (TD-HF), time dependent density functional theroy (TD-DFT), and complete-active-space self-consistent-field (CASSCF) methods are applied with a supermolecule approach and compared to the previously established monomer transition density method and the ideal dipole approximation. Strong and physically incorrect admixture of charge-transfer states makes TD-DFT inappropriate for investigations of potential energy surfaces in such dimer systems. CIS, TD-HF and CASSCF perform qualitatively correct. TD-HF seems to be a particularly appropriate method due to its general applicability and overall good performance for the excited state and for transition properties. Double-zeta basis sets with polarisation functions are found to be sufficient to predict transfer rates of dipole allowed excitations. Efficient excitation energy transfer is predicted between degenerate excited states while avoided curve crossings of nearly spaced {pi}-aggregates are identified as a possible trapping mechanism.

  14. Proton transfer in phenol-amine complexes: phenol electronic effects on free energy profile in solution.

    Science.gov (United States)

    Aono, Shinji; Kato, Shigeki

    2010-12-01

    Free energy profiles for the proton transfer reactions in hydrogen-bonded complex of phenol with trimethylamine in methyl chloride solvent are studied with the reference interaction site model self-consistent field method. The reactions in both the electronic ground and excited states are considered. The second-order Møller-Plesset perturbation (MP) theory or the second-order multireference MP theory is used to evaluate the effect of the dynamical electron correlation on the free energy profiles. The free energy surface in the ground state shows a discrepancy with the experimental results for the related hydrogen-bonded complexes. To resolve this discrepancy, the effects of chloro-substitutions in phenol are examined, and its importance in stabilizing the ionic form is discussed. The temperature effect is also studied. In contrast to the ground state, the ππ* excited state of phenol-trimethylamine complex exhibits the proton transfer reaction with a low barrier. The reaction is almost thermoneutral. This is attributed to the reduction of proton affinity of phenol by the ππ* electronic excitation. We further examine the possibility of the electron-proton-coupled transfer in the ππ* state through the surface crossing with the charge transfer type πσ* state. © 2010 Wiley Periodicals, Inc.

  15. 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.

  16. 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).

  17. Synergistic "ping-pong" energy transfer for efficient light activation in a chromophore-catalyst dyad.

    Science.gov (United States)

    Quaranta, Annamaria; Charalambidis, Georgios; Herrero, Christian; Margiola, Sofia; Leibl, Winfried; Coutsolelos, Athanassios; Aukauloo, Ally

    2015-10-07

    The synthesis of a porphyrin-Ru(II) polypyridine complex where the porphyrin acts as a photoactive unit and the Ru(II) polypyridine as a catalytic precursor is described. Comparatively, the free base porphyrin was found to outperform the ruthenium based chromophore in the yield of light induced electron transfer. Mechanistic insights indicate the occurrence of a ping-pong energy transfer from the (1)LC excited state of the porphyrin chromophore to the (3)MCLT state of the catalyst and back to the (3)LC excited state of the porphyrin unit. The latter, triplet-triplet energy transfer back to the chromophore, efficiently competes with fast radiationless deactivation of the excited state at the catalyst site. The energy thus recovered by the chromophore allows improved yield of formation of the oxidized form of the chromophore and concomitantly of the oxidation of the catalytic unit by intramolecular charge transfer. The presented results are among the rare examples where a porphyrin chromophore is successfully used to drive an oxidative activation process where reductive processes prevail in the literature.

  18. On the inverse transfer of (non-)helical magnetic energy in a decaying magnetohydrodynamic turbulence

    Science.gov (United States)

    Park, Kiwan

    2017-12-01

    In our conventional understanding, large-scale magnetic fields are thought to originate from an inverse cascade in the presence of magnetic helicity, differential rotation or a magneto-rotational instability. However, as recent simulations have given strong indications that an inverse cascade (transfer) may occur even in the absence of magnetic helicity, the physical origin of this inverse cascade is still not fully understood. We here present two simulations of freely decaying helical and non-helical magnetohydrodynamic (MHD) turbulence. We verified the inverse transfer of helical and non-helical magnetic fields in both cases, but we found the underlying physical principles to be fundamentally different. In the former case, the helical magnetic component leads to an inverse cascade of magnetic energy. We derived a semi-analytic formula for the evolution of large-scale magnetic field using α coefficient and compared it with the simulation data. But in the latter case, the α effect, including other conventional dynamo theories, is not suitable to describe the inverse transfer of non-helical magnetic energy. To obtain a better understanding of the physics at work here, we introduced a `field structure model' based on the magnetic induction equation in the presence of inhomogeneities. This model illustrates how the curl of the electromotive force leads to the build up of a large-scale magnetic field without the requirement of magnetic helicity. And we applied a quasi-normal approximation to the inverse transfer of magnetic energy.

  19. 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.

  20. High-precision gas gain and energy transfer measurements in Ar–CO{sub 2} mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Şahin, Özkan, E-mail: osahin@uludag.edu.tr [Department of Physics, Uludağ University, 16059 Bursa (Turkey); Kowalski, Tadeusz Z. [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Kraków (Poland); Veenhof, Rob [Department of Physics, Uludağ University, 16059 Bursa (Turkey); RD51 collaboration, CERN, Genève (Switzerland)

    2014-12-21

    Ar–CO{sub 2} is a Penning mixture since a fraction of the energy stored in Ar 3p{sup 5}3d and higher excited states can be transferred to ionize CO{sub 2} molecules. In the present work, concentration and pressure dependence of Penning transfer rate and photon feedback parameter in Ar–CO{sub 2} mixtures have been investigated with recent systematic high-precision gas gain measurements which cover the range 1–50% CO{sub 2} at 400, 800, 1200, 1800 hPa and gas gain from 1 to 5×10{sup 5}.

  1. Laminar heat transfer in a moving bed channel using a two energy equation model

    Energy Technology Data Exchange (ETDEWEB)

    Pivem, Ana Cristina; Lemos, Marcelo J.S. de [Departamento de Energia, IEME, Instituto Tecnologico de Aeronautica - ITA, Sao Jose dos Campos, SP (Brazil)], E-mails: anapivem@ita.br, delemos@ita.br

    2010-07-01

    The objective of this work is to present simulations for laminar heat transfer in a porous reactor, in which both the permeable bed and the working fluid moves with respect to the fixed bounding walls. For simulating the flow and heat transfer, a two-energy equation model is applied in addition to a mechanical model. Transport equations are discretized using the control-volume method and the system of algebraic equations are relaxed via the SIMPLE algorithm. The effects of solid-to-fluid thermal conductivity and solid-to-fluid ratio of thermal capacity are analyzed. (author)

  2. Comment on the article "Investigation of Fluorescence Resonance Energy Transfer between Fluorescein and Rhodamine 6G"

    Science.gov (United States)

    Joshi, Neeraj Kumar; Pant, Sanjay; Joshi, Hem Chandra

    2017-03-01

    In this comment we, report the missing of relevant literature regarding Forster energy transfer (FRET) between fluorescein and rhodamine 6G in a recent paper (Spectrochim. Acta A, 149 (2015) 143-149). In this paper, the authors claim that "a new FRET pair" has been identified, which is absolutely incorrect. In fact, studies on FRET in this dye pair under different conditions have been done earlier. Further, the estimated critical transfer distance may have uncertainty because of donor quantum yield which is not clarified in the paper.

  3. Nuclear fragmentation energy and momentum transfer distributions in relativistic heavy-ion collisions

    Science.gov (United States)

    Khandelwal, Govind S.; Khan, Ferdous

    1989-01-01

    An optical model description of energy and momentum transfer in relativistic heavy-ion collisions, based upon composite particle multiple scattering theory, is presented. Transverse and longitudinal momentum transfers to the projectile are shown to arise from the real and absorptive part of the optical potential, respectively. Comparisons of fragment momentum distribution observables with experiments are made and trends outlined based on our knowledge of the underlying nucleon-nucleon interaction. Corrections to the above calculations are discussed. Finally, use of the model as a tool for estimating collision impact parameters is indicated.

  4. Energy loss and charge transfer effects of low energy protons in thin organic films

    CERN Document Server

    Byrne, C M

    2000-01-01

    observed in TRIM simulations. It is possible that this might be attributed to a quasi-channelling effect in the 12-8 PDA at these low energies. Attempts were made to apply the same techniques to the study of thin films of double-stranded DNA. It proved difficult to produce reliable measurements over the considerable lengths of time the samples had to reside in a high vacuum. Energy loss measurements were nevertheless made for some of the DNA films although these, together with the estimates of film thickness, could not be used for any quantitative measurements. The energy loss and stopping power of protons with incident energies between 4.93 and 15 keV has been determined for self-supporting Langmiur-Blodgett films of polymerised 12-8 diacetylene (12-8 PDA), of 54 and 60 nm thicknesses, in a transmission mode. Energy loss as a function of both incident proton energy and energy loss as a function of angle has been determined for the two thicknesses of 12-8 PDA in this energy range and the experimental data com...

  5. Ion association in aqueous solutions probed through vibrational energy transfers among cation, anion, and water molecules.

    Science.gov (United States)

    Li, Jiebo; Bian, Hongtao; Chen, Hailong; Wen, Xiewen; Hoang, Bryan T; Zheng, Junrong

    2013-04-25

    KSCN and NH4SCN aqueous solutions were investigated with intermolecular vibrational energy transfer methods. In a KSCN/H2O (1/10 molar ratio) solution, 90% of the initial excitation of the CN stretch (~2066 cm(-1)) of the SCN(-) anion is transferred to the HOH bending mode (~1636 cm(-1)) of water molecules with an energy transfer time constant 3.1 ps. In a NH4SCN/H2O (1/10 molar ratio) solution, only 49% of the CN excitation flows to the water HOH bending mode with a time constant 6.3 ps. Most of the remaining CN excitation goes to the NH bending mode (~1460 cm(-1)) of the NH(+) cation with a time constant of 7.0 ps. The results indicate that about 50% of the energy transfer channel from the CN stretch to the HOH bending observed in the KSCN solution is overpowered by the NH4(+) cations in the NH4SCN/H2O solution. Ion concentration dependent measurements support this argument. According to the dipole/dipole approximation, the CN/OH energy transfer occurs most efficiently between SCN(-) anions and the water molecules closest to them. The experimental results therefore suggest that more than 50% of the water molecules closest to the SCN(-) anions are replaced by the NH4(+) cations in the NH4SCN/H2O (1/10 molar ratio) solution. The percentage is much larger than the NH4(+)/water ratio of 10%, indicating that the ion association between NH4(+) and SCN(-) is caused by the chemical nature of the solution rather than the statistical "forced contact" because of the high ion concentration.

  6. 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.)

  7. Charge Versus Energy Transfer in Atomically Thin Graphene-Transition Metal Dichalcogenide van der Waals Heterostructures

    Science.gov (United States)

    Froehlicher, Guillaume; Lorchat, Etienne; Berciaud, Stéphane

    2018-01-01

    Made from stacks of two-dimensional materials, van der Waals heterostructures exhibit unique light-matter interactions and are promising for novel optoelectronic devices. The performance of such devices is governed by near-field coupling through, e.g., interlayer charge and/or energy transfer. New concepts and experimental methodologies are needed to properly describe two-dimensional heterointerfaces. Here, we report an original study of interlayer charge and energy transfer in atomically thin metal-semiconductor [i.e., graphene-transition metal dichalcogenide (TMD, here molybdenum diselenide, MoSe2 )] heterostructures using a combination of microphotoluminescence and Raman scattering spectroscopies. The photoluminescence intensity in graphene /MoSe2 is quenched by more than 2 orders of magnitude and rises linearly with the incident photon flux, demonstrating a drastically shortened (about 1 ps) room-temperature MoSe2 exciton lifetime. Key complementary insights are provided from a comprehensive analysis of the graphene and MoSe2 Raman modes, which reveals net photoinduced electron transfer from MoSe2 to graphene and hole accumulation in MoSe2 . Remarkably, the steady-state Fermi energy of graphene saturates at 290 ±15 meV above the Dirac point. This reproducible behavior is observed both in ambient air and in vacuum and is discussed in terms of intrinsic factors (i.e., band offsets) and environmental effects. In this saturation regime, balanced photoinduced flows of electrons and holes may transfer to graphene, a mechanism that effectively leads to energy transfer. Using a broad range of incident photon fluxes and diverse environmental conditions, we find that the presence of net photoinduced charge transfer has no measurable impact on the near-unity photoluminescence quenching efficiency in graphene /MoSe2 . This absence of correlation strongly suggests that energy transfer to graphene (either in the form of electron exchange or dipole-dipole interaction) is the

  8. Charge Versus Energy Transfer in Atomically Thin Graphene-Transition Metal Dichalcogenide van der Waals Heterostructures

    Directory of Open Access Journals (Sweden)

    Guillaume Froehlicher

    2018-01-01

    Full Text Available Made from stacks of two-dimensional materials, van der Waals heterostructures exhibit unique light-matter interactions and are promising for novel optoelectronic devices. The performance of such devices is governed by near-field coupling through, e.g., interlayer charge and/or energy transfer. New concepts and experimental methodologies are needed to properly describe two-dimensional heterointerfaces. Here, we report an original study of interlayer charge and energy transfer in atomically thin metal-semiconductor [i.e., graphene-transition metal dichalcogenide (TMD, here molybdenum diselenide, MoSe_{2}] heterostructures using a combination of microphotoluminescence and Raman scattering spectroscopies. The photoluminescence intensity in graphene/MoSe_{2} is quenched by more than 2 orders of magnitude and rises linearly with the incident photon flux, demonstrating a drastically shortened (about 1 ps room-temperature MoSe_{2} exciton lifetime. Key complementary insights are provided from a comprehensive analysis of the graphene and MoSe_{2} Raman modes, which reveals net photoinduced electron transfer from MoSe_{2} to graphene and hole accumulation in MoSe_{2}. Remarkably, the steady-state Fermi energy of graphene saturates at 290±15  meV above the Dirac point. This reproducible behavior is observed both in ambient air and in vacuum and is discussed in terms of intrinsic factors (i.e., band offsets and environmental effects. In this saturation regime, balanced photoinduced flows of electrons and holes may transfer to graphene, a mechanism that effectively leads to energy transfer. Using a broad range of incident photon fluxes and diverse environmental conditions, we find that the presence of net photoinduced charge transfer has no measurable impact on the near-unity photoluminescence quenching efficiency in graphene/MoSe_{2}. This absence of correlation strongly suggests that energy transfer to graphene (either in the form of electron

  9. Data Transfer Report - 30-mm Enhanced Alternate High-Energy Propellant Program (EAHEP): Test Fixture and Propellant Evaluation

    Science.gov (United States)

    1999-01-01

    ARMY RESEARCH LABORATORY Data Transfer Report - 30-mm Enhanced Alternate High-Energy Propellant Program (EAHEP): Test Fixture and Propellant...21005-5066 ARL-SR-88 January 1999 Data Transfer Report - 30-mm Enhanced Alternate High-Energy Propellant Program (EAHEP): Test Fixture and...blank) 2. REPORT DATE January 1999 3. REPORT TYPE AND DATES COVERED Final, Mar 96-Feb 97 4. TITLE AND SUBTITLE Data Transfer Report - 30-mm

  10. The effect of intramolecular quantum modes on free energy relationships for electron transfer reactions

    DEFF Research Database (Denmark)

    Ulstrup, Jens; Jortner, Joshua

    1975-01-01

    -frequency intramolecular degrees of feedom on the free energy relationship for series of closely related reactions was investigated for various model systems involving displacement of potential energy surfaces, frequency shift, and anharmonicity effects. The free energy plots are generally found to pass through a maximum...... and to be asymmetric with a slower decrease in the transition probability with increasing energy of reaction. For high-frequency intramolecular modes this provides a rationalization of the experimental observation of ''activationless'' regions. Isotope effects are discussed as also are the oscillatory free energy......A general quantum mechanical description of exothermic electron transfer reactions is formulated by treating such reactions as the nonradiative decay of a ''supermolecule'' consisting of the electron donor, the electron acceptor, and the polar solvent. In particular, the role of the high...

  11. Decoherence approach to energy transfer and work done by slowly driven systems

    Science.gov (United States)

    Wang, Wen-ge

    2018-01-01

    A main problem, which is met when computing the energy transfer of or work done by a quantum system, comes from the fact that the system may lie in states with coherence in its energy eigenstates. As is well known, when the so-called environment-induced decoherence has happened with respect to a preferred basis given by the energy basis, no coherence exists among the energy basis and the energy change of the system can be computed in a definite way. I argue that one may make use of this property, in the search for an appropriate definition of quantum work for a total system that does not include any measuring apparatus. To show how this idea may work, in this paper, I study decoherence properties of a generic slowly driven system, which is weakly coupled to a huge environment whose main body is a complex quantum system. It is shown that decoherence may generically happen for such a system.

  12. Photon mass energy transfer coefficients for elements z=1 to 92 and 48 additional substances of dosimetric interest.

    Science.gov (United States)

    Kato, Hideki

    2014-07-01

    Photon mass energy transfer coefficient is an essential factor when converting photon energy fluence into kinetic energy released per unit mass (kerma). Although mass attenuation coefficient and mass energy absorption coefficients can be looked up in databases, the mass energy transfer coefficient values are still controversial. In this paper, the photon mass energy transfer coefficients for elements Z=1-92 were calculated based on cross-sectional data for each photon interaction type. Mass energy transfer coefficients for 48 compounds and/or mixtures of dosimetric interest were calculated from coefficient data for elements using Bragg's additivity rule. We additionally developed software that can search these coefficient data for any element or substance of dosimetric interest. The database and software created in this paper should prove useful for radiation measurements and/or dose calculations.

  13. Energy Flow and Rapidity Gaps Between Jets in Photoproduction at HERA

    CERN Document Server

    Adloff, C.; Andrieu, B.; Anthonis, T.; Arkadov, V.; Astvatsatourov, A.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bate, P.; Becker, J.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Benisch, T.; Berger, C.; Berndt, T.; Bizot, J.C.; Boehme, J.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruckner, W.; Bruncko, D.; Burger, J.; Busser, F.W.; Bunyatyan, A.; Burrage, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cao, Jun; Caron, S.; Cassol-Brunner, F.; Clarke, D.; Collard, C.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cousinou, M.C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Davidsson, M.; Delcourt, B.; Delerue, N.; Demirchyan, R.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dixon, P.; Dodonov, V.; Dowell, J.D.; Droutskoi, A.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Ferron, S.; Fleischer, M.; Fleming, Y.H.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Grab, C.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Hadig, T.; Haidt, D.; Hajduk, L.; Haller, J.; Haynes, W.J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Heremans, R.; Herrera, G.; Herynek, I.; Hildebrandt, M.; Hilgers, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hurling, S.; Ibbotson, M.; Issever, C .; Jacquet, M.; Jaffre, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, C.; Johnson, D.P.; Jones, M.A.S.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnick, O.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kermiche, S.; Kiesling, Christian M.; Kjellberg, P.; Klein, M.; Kleinwort, C.; Kluge, T.; Knies, G.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Kotelnikov, S.K.; Koutouev, R.; Koutov, A.; Krehbiel, H.; Kroseberg, J.; Kruger, K.; Kupper, A.; Kuhr, T.; Kurca, T.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebailly, E.; Lebedev, A.; Leissner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstroem, M.; List, B.; Lobodzinska, E.; Lobodzinski, B.; Loginov, A.; Loktionova, N.; Lubimov, V.; Luders, S.; Luke, D.; Lytkin, L.; Mahlke-Kruger, H.; Malden, N.; Malinovski, E.; Malinovski, I.; Maracek, R.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.U.; Martyniak, J.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Meyer, P.O.; Mikocki, S.; Milstead, D.; Mkrtchyan, T.; Mohr, R.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Nellen, G.; Newman, Paul R.; Nicholls, T.C.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Potachnikova, I.; Povh, B.; Radel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Schatzel, S.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, D.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Chekelian, V.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Straumann, U.; Swart, M.; Tasevsky, M.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tobien, N.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vassiliev, S.; Vazdik, Y.; Vichnevski, A.; Wacker, K.; Wagner, J.; Wallny, R.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; Werner, C.; Werner, M.; Werner, N.; Wessels, M.; White, G.; Wiesand, S.; Wilksen, T.; Winde, M.; Winter, G.G.; Wissing, C.; Wobisch, M.; Woehrling, E.E.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; zur Nedden, M.

    2002-01-01

    Dijet events in photon-proton collisions in which there is a large pseudorapidity separation Delta eta > 2.5 between the two highest E_T jets are studied with the H1 detector at HERA. The inclusive dijet cross sections are measured as functions of the longitudinal momentum fractions of the proton and photon which participate in the production of the jets, x_pjet and x_gjet respectively, Delta eta, the pseudorapidity separation between the two highest E_T jets, and E_T^gap, the total summed transverse energy between the jets. Rapidity gap events are defined as events in which E_T^gap is less than E_T^cut, for E_T^cut varied between 0.5 and 2.0 GeV. The fraction of dijet events with a rapidity gap is measured differentially in Delta eta, x_pjet and x_gjet. An excess of events with rapidity gaps at low values of E_T^cut is observed above the expectation from standard photoproduction processes. This excess can be explained by the exchange of a strongly interacting colour singlet object between the jets.

  14. Efficient energy transfer in light-harvesting systems, I: optimal temperature, reorganization energy and spatial-temporal correlations

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jianlan; Liu Fan; Shen Young; Cao Jianshu; Silbey, Robert J, E-mail: jianshu@mit.ed, E-mail: silbey@mit.ed [Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2010-10-15

    Understanding the mechanisms of efficient and robust energy transfer in light-harvesting systems provides new insights for the optimal design of artificial systems. In this paper, we use the Fenna-Matthews-Olson (FMO) protein complex and phycocyanin 645 (PC 645) to explore the general dependence on physical parameters that help maximize the efficiency and maintain its stability. With the Haken-Strobl model, the maximal energy transfer efficiency (ETE) is achieved under an intermediate optimal value of dephasing rate. To avoid the infinite temperature assumption in the Haken-Strobl model and the failure of the Redfield equation in predicting the Forster rate behavior, we use the generalized Bloch-Redfield (GBR) equation approach to correctly describe dissipative exciton dynamics, and we find that maximal ETE can be achieved under various physical conditions, including temperature, reorganization energy and spatial-temporal correlations in noise. We also identify regimes of reorganization energy where the ETE changes monotonically with temperature or spatial correlation and therefore cannot be optimized with respect to these two variables.

  15. 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.

  16. 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.

  17. 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.

  18. The Taylor-Proudman column in a rapidly-rotating compressible fluid I. energy transports

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jun Sang [Halla University, Wonju (Korea, Republic of)

    2014-10-15

    A theoretical study is made of the steady flow of a compressible fluid in a rapidly rotating finite cylinder. Flow is generated by imposing mechanical and/or thermal disturbances at the rotating endwall disks. Both the Ekman and Rossby numbers are small. An examination is made of the energy budget for a control volume in the Ekman boundary layer. A combination of physical variables, which is termed the energy flux content, consisting of temperature and modified angular momentum, emerges to be relevant. The distinguishing features of a compressible fluid, in contrast to those of an incompressible fluid, are noted. A plausible argument is given to explain the difficulty in achieving the Taylor-Proudman column in a compressible rotating fluid. For the Taylor-Proudman column to be sustained, in the interior, it is shown that the net energy transport between the solid disk wall and the interior fluid should vanish. Physical rationalizations are facilitated by resorting to the concept of the afore-stated energy flux content.

  19. A transferable approach towards rapid inventory data capturing for seismic vulnerability assessment using open-source geospatial technologies

    Science.gov (United States)

    Wieland, M.; Pittore, M.; Parolai, S.; Zschau, J.

    2012-04-01

    Geospatial technologies are increasingly being used in pre-disaster vulnerability assessment and post-disaster impact assessment for different types of hazards. Especially the use of remote sensing data has been strongly promoted in recent years due to its capabilities of providing up-to-date information over large areas at a comparatively low cost with increasingly high spatial, temporal and spectral resolution. Despite its clear potentials, a purely remote sensing based approach has its limitations in that it is only capable of providing information about the birds-eye view of the objects of interest. The use of omnidirectional imaging in addition can provide the necessary street-view that furthermore allows for a rapid visual screening of a buildings façade. In this context, we propose an integrated approach to rapid inventory data capturing for the assessment of structural vulnerability of buildings in case of an earthquake. Globally available low-cost data sources are preferred and the tools are developed on an open-source basis to allow for a high degree of transferability and usability. On a neighbourhood scale medium spatial but high temporal and spectral resolution satellite images are analysed to outline areas of homogeneous urban structure. Following a proportional allocation scheme, for each urban structure type representative sample areas are selected for a more detailed analysis of the building stock with high resolution image data. On a building-by-building scale a ground-based, rapid visual survey is performed using an omnidirectional imaging system driven around with a car inside the identified sample areas. Processing of the acquired images allows for an extraction of vulnerability-related features of single buildings (e.g. building height, detection of soft-storeys). An analysis of high resolution satellite images provides with further inventory features (e.g. footprint area, shape irregularity). Since we are dealing with information coming from

  20. A Rapid Transfer Alignment Method for SINS Based on the Added Backward-Forward SINS Resolution and Data Fusion

    Directory of Open Access Journals (Sweden)

    Xixiang Liu

    2013-01-01

    Full Text Available Two viewpoints are given: (1 initial alignment of strapdown inertial navigation system (SINS can be fulfilled with a set of inertial sensor data; (2 estimation time for sensor errors can be shortened by repeated data fusion on the added backward-forward SINS resolution results and the external reference data. Based on the above viewpoints, aiming to estimate gyro bias in a shortened time, a rapid transfer alignment method, without any changes for Kalman filter, is introduced. In this method, inertial sensor data and reference data in one reference data update cycle are stored, and one backward and one forward SINS resolutions are executed. Meanwhile, data fusion is executed when the corresponding resolution ends. With the added backward-forward SINS resolution, in the above mentioned update cycle, the estimating operations for gyro bias are added twice, and the estimation time for it is shortened. In the ship swinging condition, with the “velocity plus yaw” matching, the effectiveness of this method is proved by the simulation.

  1. A Multifunctional Mn(II) Phosphonate for Rapid Separation of Methyl Orange and Electron-Transfer Photochromism.

    Science.gov (United States)

    Gao, Chao-Ying; Yang, Yang; Ai, Jing; Tian, Hong-Rui; Li, Lei-Jiao; Yang, Weiting; Dang, Song; Sun, Zhong-Ming

    2016-08-08

    A Mn(II) phosphonate of the general formula [Mn(H2 L)2 (H2 O)2 (H2 bibp)] adopts a layered motif with protonated H2 bibp(2+) cations embedded in the channels (H4 L=thiophene-2-phosphonic acid; bibp=4,4'-bis(1-imidazolyl)biphenyl). The title compound exhibits excellent adsorptive removal of methyl orange (MO) dye from aqueous solution. Its advantageous features include fast adsorption, high uptake capacity, selective removal, and reusability, which are of great significance for practical application in wastewater treatment. Meanwhile, the compound displays rapid photochromism upon irradiation with visible light at room temperature. Extensive research has demonstrated that such behavior is based on a ligand-to-ligand charge-transfer (LLCT) mechanism. The irradiated sample possesses an ultra-long-lived charge-separated state. Moreover, not only is the compound the first Mn-based photochromic MOF, but it is also one of the very few examples showing LLCT with non-photochromic components. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Surface plasmon enhanced energy transfer in metal-semiconductor hybrid nanostructures.

    Science.gov (United States)

    Zhao, Xinhong; Wang, Peng; Li, Baojun

    2011-08-01

    We report a type of hybrid nanostructures composed of ZnO nanoparticles, CdSe/ZnS core/shell quantum dots (QDs), and Ag nanoprisms. With ultraviolet light illumination, the energy absorbed by ZnO nanoparticles was transferred to the CdSe/ZnS core/shell QDs inducing a photoluminescence (PL) emission. To enhance the PL emission, Ag nanoprisms were doped in the ZnO nanoparticles and the QDs. Enhanced energy transfer from the ZnO nanoparticles to the QDs via the surface plasmon effect of the Ag nanoprisms was also demonstrated. The PL emission dependence was investigated as a function of the doped Ag nanoprism concentration and a 7.4 times PL enhancement was obtained at an Ag nanoprism concentration of 5 × 10(-8) M. This journal is © The Royal Society of Chemistry 2011

  3. 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

  4. 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.

  5. Preliminary assessment of land–air energy transfers in tropical forest and agro-ecosystems

    Directory of Open Access Journals (Sweden)

    Arika Bridhikitti

    2017-04-01

    Full Text Available This study aims to show preliminary results of meteorology and surface energy transfers in tropical forests and agroecosystems and their associations with vegetation canopy and soil water content. Field observations were conducted at the selected vegetation sites and adjacent sparse vegetation sites in the Northeast of Thailand from the summer season to early rainy season. The study results showed that diurnal variations on spatial soil temperature gradient between bare soil and vegetation soil was significant but not much for air temperature and humidity. Influenced by season and cropping cycle, soil water content (SWC could induce greater spatial air temperature and humidity differences and moderated the spatial soil temperature gradient. Among various vegetation covers, diurnal patterns on energy transfers and associations between SWC and latent heat were clearly different and they suggest substantial microclimate changes associated with the conversion of forests into croplands.

  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. Differences in energy transfer of a cyanobacterium, Synechococcus sp. PCC 7002, grown in different cultivation media.

    Science.gov (United States)

    Niki, Kenta; Aikawa, Shimpei; Yokono, Makio; Kondo, Akihiko; Akimoto, Seiji

    2015-08-01

    Currently, cyanobacteria are regarded as potential biofuel sources. Large-scale cultivation of cyanobacteria in seawater is of particular interest because seawater is a low-cost medium. In the present study, we examined differences in light-harvesting and energy transfer processes in the cyanobacterium Synechococcus sp. PCC 7002 grown in different cultivation media, namely modified A medium (the optimal growth medium for Synechococcus sp. PCC 7002) and f/2 (a seawater medium). The concentrations of nitrate and phosphate ions were varied in both media. Higher nitrate ion and/or phosphate ion concentrations yielded high relative content of phycobilisome. The cultivation medium influenced the energy transfers within phycobilisome, from phycobilisome to photosystems, within photosystem II, and from photosystem II to photosystem I. We suggest that the medium also affects charge recombination at the photosystem II reaction center and formation of a chlorophyll-containing complex.

  8. EPR investigation on radiation-induced graft copolymerization of styrene onto polyethylene: Energy transfer effects

    Energy Technology Data Exchange (ETDEWEB)

    Salih, M.A. [Dipartimento di Chimica Generale, Universita di Pavia, 27100 Pavia (Italy); Buttafava, A. [Dipartimento di Chimica Generale, Universita di Pavia, 27100 Pavia (Italy); Ravasio, U. [Dipartimento di Chimica Generale, Universita di Pavia, 27100 Pavia (Italy); Dipartimento di Ingegneria Nucleare, Politecnico di Milan (Italy); Mariani, M. [Dipartimento di Ingegneria Nucleare, Politecnico di Milan (Italy); Faucitano, A. [Dipartimento di Chimica Generale, Universita di Pavia, 27100 Pavia (Italy)]. E-mail: antonio.faucitano@unipv.it

    2007-08-15

    In this paper, energy transfer phenomena concerning the in-source graft copolymerization of styrene onto LDPE were investigated through the EPR analysis of the radical intermediates. The model solution experiments have shown a substantial deviation of the experimental G (radicals) values with respect to the additivity law, which reflect the negative effect of the styrene monomer concentration on the initiation rate of the graft copolymerization. The EPR measurements performed on polyethylene-co-styrene graft copolymers of various composition following low-temperature vacuum gamma irradiation have confirmed the decrease of the total radical yields with increasing the styrene concentration. The effect was partly attributed to the heterogeneity of the graft copolymer matrix and to the lack of molecular mobility in the solid state at low temperature, which prevents the attainment of the favourable geometrical configurations in intermolecular energy and charge transfer events.

  9. Collisional Scaling of the Energy Transfer in Drift-Wave Zonal Flow Turbulence.

    Science.gov (United States)

    Schmid, B; Manz, P; Ramisch, M; Stroth, U

    2017-02-03

    The collisionality scaling of density and potential coupling together with zonal flow energy transfer and spectral power is investigated at the stellarator experiment TJ-K. With a poloidal probe array, consisting of 128 Langmuir probes, density and potential fluctuations are measured on four neighboring flux surfaces simultaneously over the complete poloidal circumference. By analyzing Reynolds stress and pseudo-Reynolds stress, it is found that, for increasing collisionality, the coupling between density and potential decreases which hinders the zonal flow drive. Also, as a consequence, the nonlinear energy transfer, as well as the zonal flow contribution to the complete turbulent spectrum, decreases the same way. This is in line with theoretical expectations and is a first experimental verification of the importance of collisionality for large-scale structure formation in magnetically confined toroidal plasmas.

  10. Rapidly switching multidirectional defibrillation: reversal of ventricular fibrillation with lower energy shocks.

    Science.gov (United States)

    Viana, Marcelo A; Bassani, Rosana A; Petrucci, Orlando; Marques, Denilson A; Bassani, José Wilson M

    2014-12-01

    Cardiac arrest after open surgery has an incidence of approximately 3%, of which more than 50% of the cases are due to ventricular fibrillation. Electrical defibrillation is the most effective therapy for terminating cardiac arrhythmias associated with unstable hemodynamics. The excitation threshold of myocardial microstructures is lower when external electrical fields are applied in the longitudinal direction with respect to the major axis of cells. However, in the heart, cell bundles are disposed in several directions. Improved myocardial excitation and defibrillation have been achieved by applying shocks in multiple directions via intracardiac leads, but the results are controversial when the electrodes are not located within the cardiac chambers. This study was designed to test whether rapidly switching shock delivery in 3 directions could increase the efficiency of direct defibrillation. A multidirectional defibrillator and paddles bearing 3 electrodes each were developed and used in vivo for the reversal of electrically induced ventricular fibrillation in an anesthetized open-chest swine model. Direct defibrillation was performed by unidirectional and multidirectional shocks applied in an alternating fashion. Survival analysis was used to estimate the relationship between the probability of defibrillation and the shock energy. Compared with shock delivery in a single direction in the same animal population, the shock energy required for multidirectional defibrillation was 20% to 30% lower (P < .05) within a wide range of success probabilities. Rapidly switching multidirectional shock delivery required lower shock energy for ventricular fibrillation termination and may be a safer alternative for restoring cardiac sinus rhythm. Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  11. Proton Transfer Reaction Mass Spectrometry detects rapid changes in volatile metabolite emission by Mycobacterium smegmatis after the addition of specific antimicrobial agents

    NARCIS (Netherlands)

    Crespo, E.; Cristescu, S. M.; de Ronde, H.; Kuijper, S.; Kolk, A.H.J.; Anthony, R.M.; Harren, F. J. M.

    2011-01-01

    The metabolic activity of plants, animals or microbes can be monitored by gas headspace analysis. This can be achieved using Proton Transfer Reaction Mass Spectrometry (PTR-MS), a highly sensitive detection method for trace gas analysis. PTR-MS is rapid and can detect metabolic responses on-line as

  12. 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

  13. Transfer map approach to an optical effects of energy degraders on the perfomance of fragment separators.

    Energy Technology Data Exchange (ETDEWEB)

    Erdelyi, B.; Bandura, L.; Nolen, J.; Physics

    2009-01-01

    A second order analytical and an arbitrary order numerical procedure is developed for the computation of transfer maps of energy degraders. The incorporation of the wedges into the optics of fragment separators for next-generation exotic beam facilities, their optical effects, and the optimization of their performance is studied in detail. It is shown how to place and shape the degraders in the system such that aberrations are minimized and resolving powers are maximized.

  14. Transfer map approach to and optical effects of energy degraders in fragment separators

    Directory of Open Access Journals (Sweden)

    B. Erdelyi

    2009-01-01

    Full Text Available A second order analytical and an arbitrary order numerical procedure is developed for the computation of transfer maps of energy degraders. The incorporation of the wedges into the optics of fragment separators for next-generation exotic beam facilities, their optical effects, and the optimization of their performance is studied in detail. It is shown how to place and shape the degraders in the system such that aberrations are minimized and resolving powers are maximized.

  15. Transfer map approach to and optical effects of energy degraders in fragment separators

    Science.gov (United States)

    Erdelyi, B.; Bandura, L.; Nolen, J.

    2009-01-01

    A second order analytical and an arbitrary order numerical procedure is developed for the computation of transfer maps of energy degraders. The incorporation of the wedges into the optics of fragment separators for next-generation exotic beam facilities, their optical effects, and the optimization of their performance is studied in detail. It is shown how to place and shape the degraders in the system such that aberrations are minimized and resolving powers are maximized.

  16. Spiro-linked hyperbranched architecture in electrophosphorescent conjugated polymers for tailoring triplet energy back transfer.

    Science.gov (United States)

    Shao, Shiyang; Ma, Zhihua; Ding, Junqiao; Wang, Lixiang; Jing, Xiabin; Wang, Fosong

    2012-04-17

    A spiro-linked hyperbranched architecture has been incorporated into electrophosphorescent conjugated polymers for the first time, aiming at simultaneously tailoring the intra- and intermolecular triplet energy back transfer from the phosphorescent guest to the conjugated polymer host. Based on a prototype with this unique structure, slower decay of triplet excitons, and 5-8 fold enhancement of device efficiencies are obtained compared with the conventional blending counterpart. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. 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.

  18. 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 ...

  19. Analytic calculation of energy transfer and heat flux in a one-dimensional system

    Science.gov (United States)

    Balakrishnan, V.; van den Broeck, C.

    2005-10-01

    In the context of the problem of heat conduction in one-dimensional systems, we present an analytical calculation of the instantaneous energy transfer across a tagged particle in a one-dimensional gas of equal-mass, hard-point particles. From this, we obtain a formula for the steady-state energy flux, and identify and separate the mechanical work and heat conduction contributions to it. The nature of the Fourier law for the model, and the nonlinear dependence of the rate of mechanical work on the stationary drift velocity of the tagged particle, are analyzed and elucidated.

  20. Finite Size Corrections to the Excitation Energy Transfer in a Massless Scalar Interaction Model

    CERN Document Server

    Maeda, N; Tobita, Y; Ishikawa, K

    2016-01-01

    We study the excitation energy transfer (EET) for a simple model in which a virtual massless scalar particle is exchanged between two molecules. If the time interval is finite, then the finite size effect generally appears in a transition amplitude through the regions where the wave nature of quanta remains. We calculated the transition amplitude for EET and obtained finite size corrections to the standard formula derived by using Fermi's golden rule. These corrections for the transition amplitude appear outside the resonance energy region. The estimation in a photosynthesis system indicates that the finite size correction could reduce the EET time considerably.

  1. Ionization of Water Clusters is Mediated by Exciton Energy Transfer from Argon Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Golan, Amir; Ahmed, Musahid

    2012-01-25

    The exciton energy deposited in an argon cluster, (Arn ,< n=20>) using VUV radiation is transferred to softly ionize doped water clusters, ((H2O)n, n=1-9) leading to the formation of non-fragmented clusters. Following the initial excitation, electronic energy is channeled to ionize the doped water cluster while evaporating the Ar shell, allowing identification of fragmented and complete water cluster ions. Examination of the photoionization efficiency curve shows that cluster evaporation from excitons located above 12.6 eV are not enough to cool the energized water cluster ion, and leads to their dissociation to (H2O)n-2H+ (protonated) clusters.

  2. The Warburg effect as an adaptation of cancer cells to rapid fluctuations in energy demand.

    Directory of Open Access Journals (Sweden)

    Tamir Epstein

    Full Text Available To maintain optimal fitness, a cell must balance the risk of inadequate energy reserve for response to a potentially fatal perturbation against the long-term cost of maintaining high concentrations of ATP to meet occasional spikes in demand. Here we apply a game theoretic approach to address the dynamics of energy production and expenditure in eukaryotic cells. Conventionally, glucose metabolism is viewed as a function of oxygen concentrations in which the more efficient oxidation of glucose to CO2 and H2O produces all or nearly all ATP except under hypoxic conditions when less efficient (2 ATP/ glucose vs. about 36ATP/glucose anaerobic metabolism of glucose to lactic acid provides an emergency backup. We propose an alternative in which energy production is governed by the complex temporal and spatial dynamics of intracellular ATP demand. In the short term, a cell must provide energy for constant baseline needs but also maintain capacity to rapidly respond to fluxes in demand particularly due to external perturbations on the cell membrane. Similarly, longer-term dynamics require a trade-off between the cost of maintaining high metabolic capacity to meet uncommon spikes in demand versus the risk of unsuccessfully responding to threats or opportunities. Here we develop a model and computationally explore the cell's optimal mix of glycolytic and oxidative capacity. We find the Warburg effect, high glycolytic metabolism even under normoxic conditions, is represents a metabolic strategy that allow cancer cells to optimally meet energy demands posed by stochastic or fluctuating tumor environments.

  3. Designed azurins show lower reorganization free energies for intraprotein electron transfer

    DEFF Research Database (Denmark)

    Farver, Ole; Marshall, Nicholas M; Wherland, Scot

    2013-01-01

    and to enable potential applications in different energy conversion systems. Herein we report studies of the intramolecular ET from pulse radiolytically produced disulfide radicals to Cu(II) in rationally designed azurin mutants. In these mutants, the copper coordination sphere has been fine-tuned to span......Low reorganization free energies are necessary for fast electron transfer (ET) reactions. Hence, rational design of redox proteins with lower reorganization free energies has been a long-standing challenge, promising to yield a deeper understanding of the underlying principles of ET reactivity...... a wide range of reduction potentials while leaving the metal binding site effectively undisrupted. We find that the reorganization free energies of ET within the mutants are indeed lower than that of WT azurin, increasing the intramolecular ET rate constants almost 10-fold: changes that are correlated...

  4. An Optimal Transmission Strategy for Joint Wireless Information and Energy Transfer in MIMO Relay Channels

    Directory of Open Access Journals (Sweden)

    Dingcheng Yang

    2015-01-01

    Full Text Available An optimal resource allocation strategy for MIMO relay system is considered in simultaneous wireless information and energy transfer network, where two users with multiple antennas communicate with each other assisted by an energy harvesting MIMO relay that gathers energy from the received signal by applying time switching scheme and forwards the received signal by using the harvesting energy. It is focused on the precoder design and resource allocation strategies for the system to allocate the resources among the nodes in decode-and-forward (DF mode. Specifically, optimal precoder design and energy transfer strategy in MIMO relay channel are firstly proposed. Then, we formulate the resource allocation optimization problem. The closed-form solutions for the time and power allocation are derived. It is revealed that the solution can flexibly allocate the resource for the MIMO relay channel to maximize the sum rate of the system. Simulation results demonstrated that the performance of the proposed algorithm outperforms the traditional fixed method.

  5. Impact Vibration Attenuation for a Flexible Robotic Manipulator through Transfer and Dissipation of Energy

    Directory of Open Access Journals (Sweden)

    Yushu Bian

    2013-01-01

    Full Text Available Due to the presence of system flexibility, impact can excite severe large amplitude vibration responses of the flexible robotic manipulator. This impact vibration exhibits characteristics of remarkable nonlinearity and strong energy. The main goal of this study is to put forward an energy-based control method to absorb and attenuate large amplitude impact vibration of the flexible robotic manipulator. The method takes advantage of internal resonance and is implemented through a vibration absorber based on the transfer and dissipation of energy. The addition of the vibration absorber to the flexible arm generates a coupling effect between vibration modes of the system. By means of analysis on 2:1 internal resonance, the exchange of energy is proven to be existent. The impact vibrational energy can be transferred from the arm to the absorber and dissipated through the damping of the absorber. The results of numerical simulations are promising and preliminarily verify that the method is feasible and can be used to combat large amplitude impact vibration of the flexible manipulator undergoing rigid motion.

  6. Characterization and Modeling of Received Signal Strength and Charging Time for Wireless Energy Transfer

    Directory of Open Access Journals (Sweden)

    Uthman Baroudi

    2015-01-01

    Full Text Available Wireless sensor networks can provide effective means for monitoring and controlling a wide range of applications. Recently, tremendous effort was directed towards devising sensors powered from ambient sources such as heat, wind, and vibration. Wireless energy transfer is another source that has attractive features that make it a promising candidate for supplying power to wireless sensor nodes. This paper is concerned with characterizing and modeling the charging time and received signal strength indicator for wireless energy transfer system. These parameters play a vital role in deciding the geometry of sensor network and the routing protocols to be deployed. The development of communication protocols for wireless-powered wireless sensor networks is also improved with the knowledge of such models. These two quantities were computed from data acquired at various coordinates of the harvester relative to a fixed position of RF energy source. Data was acquired for indoor and outdoor scenarios using the commercially available PowerCast energy harvester and evaluation board. Mathematical models for both indoor and outdoor environments were developed and analyzed. A few guidelines on how to use these models were suggested. Finally, the possibility of harvesting the energy from the ambient RF power to energize wireless sensor nodes was also investigated.

  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. Energy transfer processes among emitters dispersed in a single polymer layer for colour tuning in OLEDs

    Energy Technology Data Exchange (ETDEWEB)

    Georgiadou, D.G. [Institute of Microelectronics, NCSR ' ' Demokritos' ' , 15310 Athens (Greece); Department of Chemical Engineering, National Technical University of Athens, 15780 Athens (Greece); Vasilopoulou, M.; Palilis, L.; Argitis, P. [Institute of Microelectronics, NCSR ' ' Demokritos' ' , 15310 Athens (Greece); Pistolis, G. [Institute of Physical Chemistry, NCSR ' ' Demokritos' ' , 15310 Athens (Greece); Dimotikali, D. [Department of Chemical Engineering, National Technical University of Athens, 15780 Athens (Greece)

    2008-11-15

    The energy transfer processes taking place in a single polymeric layer that enable the definition of the three primary colours (red, green and blue) in selected areas via photochemically induced emission tuning are discussed. The polymers used as hosts are two wide band gap polymers, PVK and a polyfluorenyl derivative. In the polymer matrix are dispersed the green emitter, 1-(4'-dimethyl-aminophenyl)-6-phenyl-1,3,5-hexatriene (DMA-DPH), the red emitter, 4-dimethylamino-4'-nitrostilbene (DANS) and a photoacid generator (PAG). Upon irradiation, protons are released from the PAG and they react gradually with the two emitters, causing the blue shift of the green emitter fluorescence and the extinction of the red emitter fluorescence. Depending on the protonation extent, the relative concentrations of the emitters and the exposure dose the energy transfer processes occurring inside the matrix result in definition of different colour emitting areas. The understanding of the energy transfer processes with photoluminescence experiments is a necessary first step in order to rationalize the selection of suitable components enabling the definition of the three primary colours in OLEDs. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. {beta}-Carotene to bacteriochlorophyll c energy transfer in self-assembled aggregates mimicking chlorosomes

    Energy Technology Data Exchange (ETDEWEB)

    Alster, J. [Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Praha (Czech Republic); Polivka, T. [Institute of Physical Biology, University of South Bohemia, Zamek 136, 373 33 Nove Hrady (Czech Republic); Biology Centre, Academy of Sciences of the Czech Republic, Branisovska 31, 370 05 Ceske Budejovice (Czech Republic); Arellano, J.B. [Instituto de Recursos Naturales y Agrobiologia de Salamanca (IRNASA-CSIC), Apdo. 257, 37071 Salamanca (Spain); Chabera, P. [Institute of Physical Biology, University of South Bohemia, Zamek 136, 373 33 Nove Hrady (Czech Republic); Vacha, F. [Institute of Physical Biology, University of South Bohemia, Zamek 136, 373 33 Nove Hrady (Czech Republic); Biology Centre, Academy of Sciences of the Czech Republic, Branisovska 31, 370 05 Ceske Budejovice (Czech Republic); Psencik, J., E-mail: psencik@karlov.mff.cuni.cz [Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Praha (Czech Republic); Institute of Physical Biology, University of South Bohemia, Zamek 136, 373 33 Nove Hrady (Czech Republic)

    2010-07-19

    Carotenoids are together with bacteriochlorophylls important constituents of chlorosomes, the light-harvesting antennae of green photosynthetic bacteria. Majority of bacteriochlorophyll molecules form self-assembling aggregates inside the chlorosomes. Aggregates of bacteriochlorophylls with optical properties similar to those of chlorosomes can also be prepared in non-polar organic solvents or in aqueous environments when a suitable non-polar molecule is added. In this work, the ability of {beta}-carotene to induce aggregation of bacteriochlorophyll c in aqueous buffer was studied. Excitation relaxation and energy transfer in the carotenoid-bacteriochlorophyll assemblies were measured using femtosecond and nanosecond transient absorption spectroscopy. A fast, {approx}100-fs energy transfer from the S{sub 2} state of {beta}-carotene to bacteriochlorophyll c was revealed, while no evidence for significant energy transfer from the S{sub 1} state was found. Picosecond formation of the carotenoid triplet state (T{sub 1}) was observed, which was likely generated by singlet homo-fission from the S{sub 1} state of {beta}-carotene.

  10. 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.

  11. Interfacial energies of aqueous mixtures and porous coverings for enhancing pool boiling heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Melendez, Elva [CIICAp, Universidad Autonoma del Estado de Morelos, 62210 (Mexico); Reyes, Rene [Departamento de Ingenieria Quimica y Alimentos, Universidad de las Americas Puebla, Santa Catarina Martir Cholula, Puebla 72820 (Mexico)

    2006-08-15

    The interfacial energies effects on pool boiling were measured for combinations of aqueous ethanol mixtures and cationic surfactants. The mixture with 16% ethanol by weight had the lowest contact angle (associated to the highest wettability) and produced the highest convective heat transfer coefficient, h, among the aqueous ethanol mixtures. The surfactant sodium-lauryl-sulfate added at 100 ppm (its calculated critical micelle concentration CMC) to the 16% ethanol aqueous mixture produced an additional increment of the wettability of the mixture and of the h values; other concentrations of the surfactant reduced de contact angle and h values. The effect of these interfacial energies represents a mass-transfer contribution to pool boiling and the proposal of mixture effects both as increased spreadability and as micelle states. Several randomly constructed porous coverings, contributing to the breakage of vapor slugs around the heater, were tested; produced the highest h values for average pore diameters of 0.5 mm, and covering thickness of 0.972 mm. The synergistic effect on h of the interfacial energies of mixtures at their critical micelle concentration, and porous coverings was measured. Therefore, the independent driving forces combined in this study for increasing pool boiling heat transfer are (a) spreadability of the liquid on the solid; (b) the bubble's size reduction, achieved by micelle states; and (c) the bubble's breakage, induced by the porous coverings, for vapor flow not under pressure drop control. (author)

  12. Electron transfer energies and dipole moments of alkyl halides and amines from an electrostatic model

    Science.gov (United States)

    Applequist, Jon; Felder, Clifford E.

    1981-08-01

    Energies of the electron transfer reaction CH3X+RX+→CH3X++RX and dipole moments of molecules RX, where R is an alkyl group and X = Cl, Br, I, or NH2, are calculated for an electrostatic model in which each atom is characterized by a fixed charge and polarizability located at the position of the nucleus. The calculation takes into account the mutual polarization of the atoms in the molecular field. Atom polarizabilities are obtained from previous applications of the atom-dipole interaction model to molecular polarizabilities. Atom charges are assumed to be nonzero only for X and Cα, and these are optimized to fit 13 experimental electron transfer energies from first ionization potentials and 17 gas-phase dipole moments for selected alkyl compounds. Energies of 19 transfer reactions and dipole moments of 29 molecules are calculated, showing satisfactory overall agreement with experiment. The results suggest that the electrostatic interaction of the fixed charges with the polarizable atoms is responsible for the trend toward decreasing ionization potential with increasing size of the R group.

  13. Matching Nanoantenna Field Confinement to FRET Distances Enhances Förster Energy Transfer Rates.

    Science.gov (United States)

    Ghenuche, Petru; Mivelle, Mathieu; de Torres, Juan; Moparthi, Satish Babu; Rigneault, Hervé; Van Hulst, Niek F; García-Parajó, María F; Wenger, Jérôme

    2015-09-09

    Förster resonance energy transfer (FRET) is widely applied in chemistry, biology, and nanosciences to assess distances on sub-10 nm scale. Extending the range and applicability of FRET requires enhancement of the fluorescence energy transfer at a spatial scale comparable to the donor-acceptor distances. Plasmonic nanoantennas are ideal to concentrate optical fields at a nanoscale fully matching the FRET distance range. Here, we present a resonant aluminum nanogap antenna tailored to enhance single molecule FRET. A 20 nm gap confines light into a nanoscale volume, providing a field gradient on the scale of the donor-acceptor distance, a large 10-fold increase in the local density of optical states, and strong intensity enhancement. With our dedicated design, we obtain 20-fold enhancement on the fluorescence emission of donor and acceptor dyes, and most importantly up to 5-fold enhancement of the FRET rate for donor-acceptor separations of 10 nm. We also provide a thorough framework of the fluorescence photophysics occurring in the nanoscale gap volume. The presented enhancement of energy transfer flow at the nanoscale opens a yet unexplored facet of the various advantages of optical nanoantennas and provides a new strategy toward biological applications of single molecule FRET at micromolar concentrations.

  14. 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.

  15. Noise-assisted energy transfer in quantum networks and light-harvesting complexes

    Energy Technology Data Exchange (ETDEWEB)

    Chin, A W; Caruso, F; Huelga, S F; Plenio, M B [Institut fuer Theoretische Physik, Universitaet Ulm, D-89069, Ulm (Germany); Datta, A, E-mail: alex.chin@uni-ulm.d [Institute for Mathematical Sciences, Imperial College London, 53 Exhibition Road, London SW7 2PG (United Kingdom)

    2010-06-15

    We provide physically intuitive mechanisms for the effect of noise on excitation energy transfer (EET) in networks. Using these mechanisms of dephasing-assisted transport (DAT) in a hybrid basis of both excitons and sites, we develop a detailed picture of how noise enables energy transfer with efficiencies well above 90% across the Fenna-Matthew-Olson (FMO) complex, a type of light-harvesting molecule. We demonstrate explicitly how noise alters the pathways of energy transfer across the complex, suppressing ineffective pathways and facilitating direct ones to the reaction centre. We explain that the fundamental mechanisms underpinning DAT are expected to be robust with respect to the considered noise model but show that the specific details of the exciton-phonon coupling, which remain largely unknown in these type of complexes, and in particular the impact of non-Markovian effects, result in variations of dynamical features that should be amenable to experimental verification with current or planned technology. A detailed understanding of DAT in natural compounds could open up a new paradigm of 'noise-engineering' by which EET can be optimized in artificial light-harvesting structures.

  16. Efficient phosphorescent polymer light-emitting diodes by suppressing triplet energy back transfer.

    Science.gov (United States)

    Gong, Shaolong; Yang, Chuluo; Qin, Jingui

    2012-07-21

    Phosphorescent polymer light-emitting diodes (PhPLEDs) are promising devices in flat panel displays and solid state lighting sources since they can combine the advantages of the high efficiency of electrophosphorescence and low-cost, large-scale manufacture by using a solution process. However, their efficiencies are generally much lower than those of small-molecule-based devices fabricated by using a thermal deposition approach. One of the major reasons for their low efficiency is that energy is lost by back transfer to a polymer host. This tutorial review gives a brief introduction to the fundamentals of PhPLEDs, and then highlights recent progress in the main approaches to suppress triplet energy back transfer from the phosphor to the polymer host towards realizing highly efficient PhPLEDs. The suppressing mechanisms are discussed, and the achievement of high device efficiencies are demonstrated. Emphasis is placed on the relationships between molecular structure, the extent of suppressing triplet energy back transfer, and device performance.

  17. Simultaneous gene transfer of bone morphogenetic protein (BMP -2 and BMP-7 by in vivo electroporation induces rapid bone formation and BMP-4 expression

    Directory of Open Access Journals (Sweden)

    Miyazaki Jun-ichi

    2006-08-01

    Full Text Available Abstract Background Transcutaneous in vivo electroporation is expected to be an effective gene-transfer method for promoting bone regeneration using the BMP-2 plasmid vector. To promote enhanced osteoinduction using this method, we simultaneously transferred cDNAs for BMP-2 and BMP-7, as inserts in the non-viral vector pCAGGS. Methods First, an in vitro study was carried out to confirm the expression of BMP-2 and BMP-7 following the double-gene transfer. Next, the individual BMP-2 and BMP-7 plasmids or both together were injected into rat calf muscles, and transcutaneous electroporation was applied 8 times at 100 V, 50 msec. Results In the culture system, the simultaneous transfer of the BMP-2 and BMP-7 genes led to a much higher ALP activity in C2C12 cells than did the transfer of either gene alone. In vivo, ten days after the treatment, soft X-ray analysis showed that muscles that received both pCAGGS-BMP-2 and pCAGGS-BMP-7 had better-defined opacities than those receiving a single gene. Histological examination showed advanced ossification in calf muscles that received the double-gene transfer. BMP-4 mRNA was also expressed, and RT-PCR showed that its level increased for 3 days in a time-dependent manner in the double-gene transfer group. Immunohistochemistry confirmed that BMP-4-expressing cells resided in the matrix between muscle fibers. Conclusion The simultaneous transfer of BMP-2 and BMP-7 genes using in vivo electroporation induces more rapid bone formation than the transfer of either gene alone, and the increased expression of endogenous BMP-4 suggests that the rapid ossification is related to the induction of BMP-4.

  18. An edge-on charge-transfer design for energy-resolved x-ray detection

    Science.gov (United States)

    Shi, Zaifeng; Yang, Haoyu; Cong, Wenxiang; Wang, Ge

    2016-06-01

    As an x-ray beam goes through the human body, it will collect important information via interaction with tissues. Since this interaction is energy-sensitive, the state-of-the-art spectral CT technologies provide higher quality images of biological tissues with x-ray energy information (or spectral information). With existing energy-integrating technologies, a large fraction of energy information is ignored in the x-ray detection process. Although the recently proposed photon-counting technology promises to achieve higher image quality at a lower radiation dose, it suffers from limitations in counting rate, performance uniformity, and fabrication cost. In this paper, we focus on an alternative approach to resolve the energy distribution of transmitted x-ray photons. First, we analyze the x-ray attenuation in a silicon substrate and describe a linear approximation model for x-ray detection. Then, we design an edge-on architecture based on the proposed energy-resolving model. In our design, the x-ray-photon-induced charges are transferred sequentially resembling the working process of a CCD camera. Finally, we numerically evaluate the linear approximation of x-ray attenuation and derive the energy distribution of x-ray photons. Our simulation results show that the proposed energy-sensing approach is feasible and has the potential to complement the photon-counting technology.

  19. Energy release and transfer in solar flares: simulations of three-dimensional reconnection

    Energy Technology Data Exchange (ETDEWEB)

    Birn, Joachim [Los Alamos National Laboratory; Fletches, L [UNIV OF GLASGOW; Hesse, M [HGSFC; Neukirch, T [UNIV OF ST. ANDREWS

    2008-01-01

    Using three-dimensional magnetohydrodynamic (MHD) simulations we investigate energy release and transfer in a three-dimensional extension of the standard two-ribbon flare picture. In this scenario reconnection is initiated in a thin current sheet (suggested to form below a departing coronal mass ejection) above a bipolar magnetic field. Two cases are contrasted: an initially force-free current sheet (low beta) and a finite-pressure current sheet (high beta). The energy conversion process from reconnect ion consists of incoming Poynting flux (from the release of magnetic energy) turned into up-and downgoing Poynting flux, enthalpy flux and bulk kinetic energy flux. In the low-beta case, the outgoing Poynting flux is the dominant contribution, whereas the outgoing enthalpy flux dominates in the high-beta case. The bulk kinetic energy flux is only a minor contribution, particularly in the downward direction. The dominance of the downgoing Poynting flux in the low-beta case is consistent with an alternative to the thick target electron beam model for solar flare energy transport, suggested recently by Fletcher and Hudson. For plausible characteristic parameters of the reconnecting field configuration, we obtain energy release time scales and and energy output rates that compare favorably with those inferred from observations for the impulsive phase of flares.

  20. Transfer of energy pathway genes in microbial enhanced biological phosphorus removal communities.

    Science.gov (United States)

    Wong, Dennis H-J; Beiko, Robert G

    2015-07-16

    Lateral gene transfer (LGT) is an important evolutionary process in microbial evolution. In sewage treatment plants, LGT of antibiotic resistance and xenobiotic degradation-related proteins has been suggested, but the role of LGT outside these processes is unknown. Microbial communities involved in Enhanced Biological Phosphorus Removal (EBPR) have been used to treat wastewater in the last 50 years and may provide insights into adaptation to an engineered environment. We introduce two different types of analysis to identify LGT in EBPR sewage communities, based on identifying assembled sequences with more than one strong taxonomic match, and on unusual phylogenetic patterns. We applied these methods to investigate the role of LGT in six energy-related metabolic pathways. The analyses identified overlapping but non-identical sets of transferred enzymes. All of these were homologous with sequences from known mobile genetic elements, and many were also in close proximity to transposases and integrases in the EBPR data set. The taxonomic method had higher sensitivity than the phylogenetic method, identifying more potential LGTs. Both analyses identified the putative transfer of five enzymes within an Australian community, two in a Danish community, and none in a US-derived culture. Our methods were able to identify sequences with unusual phylogenetic or compositional properties as candidate LGT events. The association of these candidates with known mobile elements supports the hypothesis of transfer. The results of our analysis strongly suggest that LGT has influenced the development of functionally important energy-related pathways in EBPR systems, but transfers may be unique to each community due to different operating conditions or taxonomic composition.

  1. Relative significance of heat transfer processes to quantify tradeoffs between complexity and accuracy of energy simulations with a building energy use patterns classification

    Science.gov (United States)

    Heidarinejad, Mohammad

    This dissertation develops rapid and accurate building energy simulations based on a building classification that identifies and focuses modeling efforts on most significant heat transfer processes. The building classification identifies energy use patterns and their contributing parameters for a portfolio of buildings. The dissertation hypothesis is "Building classification can provide minimal required inputs for rapid and accurate energy simulations for a large number of buildings". The critical literature review indicated there is lack of studies to (1) Consider synoptic point of view rather than the case study approach, (2) Analyze influence of different granularities of energy use, (3) Identify key variables based on the heat transfer processes, and (4) Automate the procedure to quantify model complexity with accuracy. Therefore, three dissertation objectives are designed to test out the dissertation hypothesis: (1) Develop different classes of buildings based on their energy use patterns, (2) Develop different building energy simulation approaches for the identified classes of buildings to quantify tradeoffs between model accuracy and complexity, (3) Demonstrate building simulation approaches for case studies. Penn State's and Harvard's campus buildings as well as high performance LEED NC office buildings are test beds for this study to develop different classes of buildings. The campus buildings include detailed chilled water, electricity, and steam data, enabling to classify buildings into externally-load, internally-load, or mixed-load dominated. The energy use of the internally-load buildings is primarily a function of the internal loads and their schedules. Externally-load dominated buildings tend to have an energy use pattern that is a function of building construction materials and outdoor weather conditions. However, most of the commercial medium-sized office buildings have a mixed-load pattern, meaning the HVAC system and operation schedule dictate

  2. Epidemiology of distal radius fractures in polytrauma patients and the influence of high traumatic energy transfer.

    Science.gov (United States)

    Ferree, Steven; van der Vliet, Quirine M J; Nawijn, Femke; Bhashyam, Abhiram R; Houwert, Roderick M; Leenen, Luke P H; Hietbrink, Falco

    2018-02-05

    For several extremity fractures differences in morphology, incidence rate and functional outcome were found when polytrauma patients were compared to patients with an isolated injury. This is not proven for distal radius fractures (DRF). Therefore, this study aimed to analyse fracture morphology in relation to energy transfer in both poly- and mono-trauma patients with a DRF. This was a retrospective cohort study. All patients aged 16 years and older with a DRF were included. Patients with an Injury Severity Score of 16 or higher were classified as polytrauma patients. Injuries were defined as high or low energy. All DRFs were classified using the AO/OTA fracture classification system. A total of 830 patients with a DRF were included, 12% were polytrauma. The incidence rate of DRF in polytrauma patients was 3.5%. Ipsilateral upper extremity injury was found in >30% of polytrauma and high-energy monotrauma patients, compared to 5% in low-energy monotrauma patients. More type C DRF were found in polytrauma and high-energy monotrauma patients versus low-energy monotrauma patients. Operative intervention rates for all types of DRF were similar for polytrauma and high-energy monotrauma patients. Non-union rates were higher in polytrauma patients. Higher energy mechanisms of injury, in polytrauma and high-energy monotrauma patients, were associated with more severe complex articular distal radius fractures and more ipsilateral upper extremity injuries. Polytrauma and high-energy monotrauma patient have a similar fracture morphology. However, polytrauma patients have in addition to more injured body regions also more non-union related interventions than high-energy monotrauma patients. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Development of compact rapid charging power supply for capacitive energy storage in pulsed power drivers.

    Science.gov (United States)

    Sharma, Surender Kumar; Shyam, Anurag

    2015-02-01

    High energy capacitor bank is used for primary electrical energy storage in pulsed power drivers. The capacitors used in these pulsed power drivers have low inductance, low internal resistance, and less dc life, so it has to be charged rapidly and immediately discharged into the load. A series resonant converter based 45 kV compact power supply is designed and developed for rapid charging of the capacitor bank with constant charging current up to 150 mA. It is short circuit proof, and zero current switching technique is used to commute the semiconductor switch. A high frequency resonant inverter switching at 10 kHz makes the overall size small and reduces the switching losses. The output current of the power supply is limited by constant on-time and variable frequency switching control technique. The power supply is tested by charging the 45 kV/1.67 μF and 15 kV/356 μF capacitor banks. It has charged the capacitor bank up to rated voltage with maximum charging current of 150 mA and the average charging rate of 3.4 kJ/s. The output current of the power supply is limited by reducing the switching frequency at 5 kHz, 3.3 kHz, and 1.7 kHz and tested with 45 kV/1.67 μF capacitor bank. The protection circuit is included in the power supply for over current, under voltage, and over temperature. The design details and the experimental testing results of the power supply for resonant current, output current, and voltage traces of the power supply with capacitive, resistive, and short circuited load are presented and discussed.

  4. 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.

  5. The energy transfer mechanism of a perturbed solid-body rotation flow in a rotating pipe

    Science.gov (United States)

    Feng, Chunjuan; Liu, Feng; Rusak, Zvi; Wang, Shixiao

    2017-04-01

    Three-dimensional direct numerical simulations of a solid-body rotation superposed on a uniform axial flow entering a rotating constant-area pipe of finite length are presented. Steady in time profiles of the radial, axial, and circumferential velocities are imposed at the pipe inlet. Convective boundary conditions are imposed at the pipe outlet. The Wang and Rusak (Phys. Fluids 8:1007-1016, 1996. doi: 10.1063/1.86882) axisymmetric instability mechanism is retrieved at certain operational conditions in terms of incoming flow swirl levels and the Reynolds number. However, at other operational conditions there exists a dominant, three-dimensional spiral type of instability mode that is consistent with the linear stability theory of Wang et al. (J. Fluid Mech. 797: 284-321, 2016). The growth of this mode leads to a spiral type of flow roll-up that subsequently nonlinearly saturates on a large amplitude rotating spiral wave. The energy transfer mechanism between the bulk of the flow and the perturbations is studied by the Reynolds-Orr equation. The production or loss of the perturbation kinetic energy is combined of three components: the viscous loss, the convective loss at the pipe outlet, and the gain of energy at the outlet through the work done by the pressure perturbation. The energy transfer in the nonlinear stage is shown to be a natural extension of the linear stage with a nonlinear saturated process.

  6. Surface energy budget from a Titan GCM with realistic radiative transfer

    Science.gov (United States)

    Lora, Juan M.; Russell, J.; Lunine, J.

    2013-10-01

    The existence of Titan's seasonal convective cloud activity, despite the atmosphere's huge thermal inertia, has been explained as resulting from variations in surface temperatures that drive cloud formation. General circulation models (GCMs) that produce significant summer precipitation have typically employed simplified radiative transfer that allows the summer polar surface to receive the maximum insolation, thus allowing vigorous convection to occur there. However, surface energetics from a GCM with nongray radiative transfer that uses optical properties derived from Cassini/Huygens data, and correlated k coefficients, indicate that this may not be entirely realistic. The surface energy budget in equilibrium is a balance between net surface radiation and turbulent surface fluxes of latent and sensible energy; because the maximum surface insolation oscillates seasonally between mid-latitudes, so too do the turbulent fluxes. Thus, the destabilizing influence of surface energy fluxes into the atmosphere with respect to convection is lower than previously suggested at the poles, but higher near midlatitudes. Methane is not available in infinite supply at the surface, and therefore sensible heat flux plays an equally important role as evaporation in balancing the surface radiative imbalance. The modeled moist static energy maximum also oscillates only between midlatitudes, in part because polar surface methane is limited as a source, boosting the possibility of midlatitude clouds. This may help to explain the observed persistence of southern mid-latitude clouds as the seasons change.

  7. Spectroscopic properties and energy transfer parameters of Er3+-doped fluorozirconate and oxyfluoroaluminate glasses.

    Science.gov (United States)

    Huang, Feifei; Liu, Xueqiang; Hu, Lili; Chen, Danping

    2014-05-23

    Er3+-doped fluorozirconate (ZrF4-BaF2-YF3-AlF3) and oxyfluoroaluminate glasses are successfully prepared here. These glasses exhibit significant superiority compared with traditional fluorozirconate glass (ZrF4-BaF2-LaF3-AlF3-NaF) because of their higher temperature of glass transition and better resistance to water corrosion. Judd-Ofelt (J-O) intensity parameters are evaluated and used to compute the radiative properties based on the VIS-NIR absorption spectra. Broad emission bands located at 1535 and 2708 nm are observed, and large calculated emission sections are obtained. The intensity of 2708 nm emission closely relates to the phonon energy of host glass. A lower phonon energy leads to a more intensive 2708 nm emission. The energy transfer processes of Er3+ ions are discussed and lifetime of Er3+:4I13/2 is measured. It is the first time to observe that a longer lifetime of the 4I13/2 level leads to a less intensive 1535 nm emission, because the lifetime is long enough to generate excited state absorption (ESA) and energy transfer (ET) processes. These results indicate that the novel glasses possess better chemical and thermal properties as well as excellent optical properties compared with ZBLAN glass. These Er3+-doped ZBYA and oxyfluoroaluminate glasses have potential applications as laser materials.

  8. Tracing of backward energy transfer from LH1 to LH2 in photosynthetic membranes grown under high and low irradiation.

    Directory of Open Access Journals (Sweden)

    Lanzani G.

    2013-03-01

    Full Text Available By introducing derivative transient absorption spectroscopy, we obtain rate constants for backward and forward energy transfer between LH1 and LH2 complexes in purple bacterial membranes. We find that backward energy transfer is strongly reduced in membranes grown under low irradiation conditions, compared to high light grown ones. We conclude that backward energy transfer is managed actively by the bacteria to avoid LH1 exciton deactivation under high irradiation conditions. The analytical method is generally applicable to excitonically coupled systems.

  9. The energy transfer from Eu2+ to Tb3+ in calcium chlorapatite phosphor and its potential application in LEDs

    Science.gov (United States)

    Zhang, Z.; Wang, J.; Zhang, M.; Zhang, Q.; Su, Q.

    2008-06-01

    Energy transfer from Eu2+ to Tb3+ was observed by investigating the optical properties from photoluminescence spectra and decay time curves in Tb3+ singly doped and Eu2+ Tb3+ co-doped calcium chlorapatite, Ca5(PO4)3Cl (CPCl). It is dominated by the cooperation of a phonon-assisted energy transfer process and a non-radiative resonant energy transfer process caused by the exchange interaction. Eu2+ Tb3+ co-doped calcium chlorapatite phosphors in which Tb3+ can be efficiently excited by 400 nm are potential candidates for phosphor-converted LED.

  10. 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

  11. The Water-Energy-Food Nexus in a Rapidly Developing Resource Sector

    Science.gov (United States)

    Allen, D. M.; Kirste, D. M.

    2014-12-01

    Technological advances and access to global markets have changed the rate at which resource exploitation takes place. The environmental impact of the rapid development and distribution of resources such as minerals and hydrocarbons has led to a greater potential for significant stress on water resources both in terms of quality and quantity. How and where those impacts manifest is crucial to determining appropriate risk management strategies. North East British Columbia has an abundance of shale gas reserves that are anticipated to be exploited at a large scale in coming years, primarily for export as liquefied natural gas (LNG). However, there is growing concern that fracking and other activities related to shale gas development pose risks to water quality and quantity in the region. Water lies at the center of the water-energy-food nexus, with an accelerating water demand for fracking and industrial operations as well as for domestic, environmental and agricultural uses. Climate change is also anticipated to alter the hydrologic regime, posing added stress to the water resource. This case study examines the water-energy-food nexus in the context of a region that is impacted by a rapidly developing resource sector, encompassing water demand/supply, climate change, interaction between deep aquifers and shallow aquifers/surface waters, water quality concerns related to fracking, land use disturbance, and community impacts. Due to the rapid rate of development, there are significant knowledge gaps in our understanding of the water resource. Currently agencies are undertaking water resource assessments and establishing monitoring sites. This research aims to assess water security in North East British Columbia in a coordinated fashion through various partnerships. In addition to collecting baseline knowledge and data, the study will evaluate risk and resilience indicators in relation to water security. A risk assessment framework specific to the shale gas development

  12. Photoinduced energy and electron transfer in phenylethynyl-bridged zinc porphyrin-oligothienylenevinylene-C60 ensembles.

    Science.gov (United States)

    Urbani, Maxence; Ohkubo, Kei; Islam, D M Shafiqul; Fukuzumi, Shunichi; Langa, Fernando

    2012-06-11

    Donor-bridge-acceptor triad (Por-2TV-C(60)) and tetrad molecules ((Por)(2)-2TV-C(60)), which incorporated C(60) and one or two porphyrin molecules that were covalently linked through a phenylethynyl-oligothienylenevinylene bridge, were synthesized. Their photodynamics were investigated by fluorescence measurements, and by femto- and nanosecond laser flash photolysis. First, photoinduced energy transfer from the porphyrin to the C(60) moiety occurred rather than electron transfer, followed by electron transfer from the oligothienylenevinylene to the singlet excited state of the C(60) moiety to produce the radical cation of oligothienylenevinylene and the radical anion of C(60). Then, back-electron transfer occurred to afford the triplet excited state of the oligothienylenevinylene moiety rather than the ground state. Thus, the porphyrin units in (Por)-2TV-C(60) and (Por)(2)-2TV-C(60) acted as efficient photosensitizers for the charge separation between oligothienylenevinylene and C(60). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Modified windmill porphyrin arrays: coupled light-harvesting and charge separattion, conformational relaxation in the S1 state, and S2-S2 energy transfer.

    Science.gov (United States)

    Nakano, A; Osuka, A; Yamazaki, T; Nishimura, Y; Akimoto, S; Yamazaki, I; Itaya, A; Murakami, M; Miyasaka, H

    2001-07-16

    The architecture of windmill hexameric zinc(II) -porphyrin array 1 is attractive as a light-harvesting functional unit in view of its three-dimensionally extended geometry that is favorable for a large cross-section of incident light as well as for a suitable energy gradient from the peripheral porphyrins to the meso-meso-linked diporphyrin core. Three core-modified windmill porphyrin arrays 2-4 were prepared for the purpose of enhancing the intramolecular energy-transfer rate and coupling these arrays with a charge-separation functional unit. Bisphenylethynylation at the meso and meso' positions of the diporphyrin core indeed resulted in a remarkable enhancement in the intramolecular S1-S1 energy transfer in 2 with tau=2 approximately 3 ps, as revealed by femtosecond time-resolved transient absorption spectroscopy. The fluorescence lifetime of the S2 state of the peripheral porphyrin energy donor determined by the fluorescence up-conversion method was 68 fs, and thus considerably shorter than that of the reference monomer (150 fs), suggesting the presence of the intramolecular energy-transfer channel in the S2 state manifold. Such a rapid energy transfer can be understood in terms of large Coulombic interactions associated with the strong Soret transitions of the donor and acceptor. Picosecond time-resolved fluorescence spectra and transient absorption spectra revealed conformational relaxation of the S1 state of the diporphyrin core with tau = 25 ps. Upon photoexcitation of models 3 and 4, which bear a naphthalenetetracarboxylic diimide or a meso-nitrated free-base porphyrin attached to the modified diporphyrin core as an electron acceptor, a series of photochemical processes proceeded, such as the collection of the excitation energy at the diporphyrin core, the electron transfer from the S1 state of the diporphyrin to the electron acceptor, and the electron transfer from the peripheral porphyrins to the diporphyrin cation radical, which are coupled to provide a

  14. The evaluation of energy efficiency of convective heat transfer surfaces in tube bundles

    Science.gov (United States)

    Grigoriev, B. A.; Pronin, V. A.; Salohin, V. I.; Sidenkov, D. V.

    2017-11-01

    When evaluating the effectiveness of the heat exchange surfaces in the main considered characteristics such as heat flow (Q, Watt), the power required for pumps (N, Watt), and surface area of heat transfer (F, m2). The most correct comparison provides a comparison “ceteris paribus”. Carried out performance comparison “ceteris paribus” in-line and staggered configurations of bundles with a circular pipes can serve as a basis for the development of physical models of flow and heat transfer in tube bundles with tubes of other geometric shapes, considering intertubular stream with attached eddies. The effect of longitudinal and transverse steps of the pipes on the energy efficiency of different configurations would take into account by mean of physical relations between the structure of shell side flow with attached eddies and intensity of transfer processes of heat and momentum. With the aim of energy-efficient placement of tubes, such an approach opens up great opportunities for the synthesis of a plurality of tubular heat exchange surfaces, in particular, the layout of the twisted and in-line-diffuser type with a drop-shaped pipes.

  15. Radical-Molecule Reaction Mechanisms: Role of Electron Delocalization, Complex Formation, and Intramolecular Energy Transfer.

    Science.gov (United States)

    Dubey, Manvendra Krishna

    This thesis presents: (1) measurements of the kinetics of the reactions of the OH radical with several molecules by the discharge flow technique, (2) reactivity trend analysis, electronic structure, and transition state calculations, (3) molecular beam electric deflection experiments of hot polyatomics. A synthesis of these studies demonstrates that radical-molecule reactions frequently involve an indirect mechanism and are not necessarily direct, activated, bimolecular processes. Indirect mechanisms arise when the reactant frontier orbitals do not transform to the product configuration. Compact reactivity trends among homologous reaction sets are defined by the difference between the ionization potential of the electron donor and the electron affinity of the electron acceptor and show that charge-transfer stabilizations (rather than thermodynamics) govern radical-molecule reactivity. A multiple transition state model is developed to predict the mixed bimolecular/termolecular kinetics implicit in the indirect mechanism. The fundamental assumption of rapid intramolecular energy redistribution in the energized complex in the model is validated by our electric deflection studies. Model calculations for the rm OH + HNO_3to H_2O + NO_3 reaction reproduce the small A factor, negative activation energy, and pressure dependence of the rate. They elucidate the reaction mechanism in molecular detail. The OH first bonds to either the O or N atom of HNO_3 to form an energized complex, which subsequently suffers one of three fates: dissociation to reactants via a loose transition state, dissociation to products via a tight transition state with a negative threshold, or collisional stabilization. These processes compete to determine the overall kinetics. Isotopic scrambling rates are predicted. Our model predicts faster rates than the NASA recommendation at low temperatures with potential consequences for stratospheric photochemistry. The rate constants of the reactions of OH

  16. Photoinduced electron transfer at the tetrapyrrole-TiO2 interface: Effect of the energy alignment

    Science.gov (United States)

    Nieto-Pescador, Jesus S.

    Photoinduced electron transfer is a ubiquitous process behind several physical, chemical, and biological processes. Its potential applications, ranging from solar cell technologies to photodynamic cancer therapy, require a thorough understanding of the basics of the reaction. This dissertation addresses open questions for a particular case of electron transfer processes: Heterogeneous Electron Transfer (HET). In this process, an electron is transferred between a localized donor and a multitude of delocalized acceptor states. HET between photoexcited tetrapyrroles and colloidal TiO2 has been investigated using femtosecond transient absorption spectroscopy. Specifically, this work explores the not well-understood influence of the availability of states on the HET reaction. This problem is addressed by measuring electron injection times as a function of the energy difference between the LUMO and the conduction band of TiO2. The change in the energy alignment was done using two experimental strategies. The first one employs a recently synthesized phlorin with two different excited states above the conduction band of TiO2. This molecule allows comparing HET rates from two different excited states. The second strategy measures the electron injection rates after exciting the same electronic state of a set of specially designed porphyrins. The novelty of the approach is that the difference in energy alignment is attained by the introduction of dipole groups within the bridge group of the molecule. This strategy generates a difference in energy alignment of up to 200 meV. The reported measurements were carried in a high vacuum environment with an apparatus capable of resolving sub 30 fs processes. Disentanglement of the electron transfer processes was done, after careful study of the relaxation dynamics of the molecules in solution, by monitoring the decay of the excited state absorption and the rise of the cation spectral signatures. Within our time resolution, our results

  17. Surge in the heating market. Renewable energies rapidly gaining market share; Wende im Waermemarkt. Erneuerbare Energien gewinnen rasant an Marktanteilen

    Energy Technology Data Exchange (ETDEWEB)

    Briese, Dirk; Hein, Thomas; Gatena, Jens [trend:research GmbH Institut fuer Trend- und Marktforschung, Bremen (Germany)

    2009-10-15

    The proportion of heat produced from renewable energies is rapidly growing in Germany. The main reasons for this dynamic development are governmental funds for heating technologies based on renewable energy, the growing importance attached by large parts of the population to environmentally responsible energy production and the rising costs of fossil fuels. Biomass plants, solar thermal installations and heat pumps will be widely used in upcoming refurbishment and new building projects, as a recent study shows.

  18. Recent advances in energy transfer in bulk and nanoscale luminescent materials: from spectroscopy to applications.

    Science.gov (United States)

    Liu, Xiaofeng; Qiu, Jianrong

    2015-12-07

    Transfer of energy occurs endlessly in our universe by means of radiation. Compared to energy transfer (ET) in free space, in solid state materials the transfer of energy occurs in a rather confined manner, which is usually mediated by real or virtual particles, including not only photons, but also electrons, phonons, and excitons. In the present review, we discuss the recent advances in optical ET by resonance mediated with photons in solid materials as well as their nanoscale counterparts, with focus on the photoluminescence behavior pertaining to ET between optically active centers, such as rare earth (RE) ions. This review begins with a brief discussion on the classification of optical ET together with an overview of the theoretical formulations and experimental method for the examination of ET. We will then present a comprehensive discussion on the ET in practical systems in which normal photoluminescence, upconversion and quantum cutting resulted from ET involving metal ions, QDs, organic species, 2D materials and plasmonic nanostructures. Diverse ET systems are therefore simply categorized into cases of ion-ion interactions and non-ion interactions. Special attention has been paid to the progress in the manipulation of spatially confined ET in nanostructured systems including core-shell structures, as well as the ET in multiple exciton generation found in QDs and organic molecules, which behave quite similarly to resonance ET between metal ion centers. Afterwards, we will discuss the broad spectrum of applications of ET in the aforementioned systems, including solid state lighting, solar energy utilization, bio-imaging and diagnosis, and sensing. In the closing part, along with a short summary, we discuss further research focus regarding the problems and possible future directions of optical ET in solids.

  19. Energy Transfer with Semiconductor Quantum Dot Bioconjugates: A Versatile Platform for Biosensing, Energy Harvesting, and Other Developing Applications.

    Science.gov (United States)

    Hildebrandt, Niko; Spillmann, Christopher M; Algar, W Russ; Pons, Thomas; Stewart, Michael H; Oh, Eunkeu; Susumu, Kimihiro; Díaz, Sebastian A; Delehanty, James B; Medintz, Igor L

    2017-01-25

    Luminescent semiconductor quantum dots (QDs) are one of the more popular nanomaterials currently utilized within biological applications. However, what is not widely appreciated is their growing role as versatile energy transfer (ET) donors and acceptors within a similar biological context. The progress made on integrating QDs and ET in biological configurations and applications is reviewed in detail here. The goal is to provide the reader with (1) an appreciation for what QDs are capable of in this context, (2) how this field has grown over a relatively short time span, and, in particular, (3) how QDs are steadily revolutionizing the development of new biosensors along with a myriad of other photonically active nanomaterial-based bioconjugates. An initial discussion of QD materials along with key concepts surrounding their preparation and bioconjugation is provided given the defining role these aspects play in the QDs ability to succeed in subsequent ET applications. The discussion is then divided around the specific roles that QDs provide as either Förster resonance energy transfer (FRET) or charge/electron transfer donor and/or acceptor. For each QD-ET mechanism, a working explanation of the appropriate background theory and formalism is articulated before examining their biosensing and related ET utility. Other configurations such as incorporation of QDs into multistep ET processes or use of initial chemical and bioluminescent excitation are treated similarly. ET processes that are still not fully understood such as QD interactions with gold and other metal nanoparticles along with carbon allotropes are also covered. Given their maturity, some specific applications ranging from in vitro sensing assays to cellular imaging are separated and discussed in more detail. Finally a perspective on how this field will continue to evolve is provided.

  20. High Excitation Transfer Efficiency from Energy Relay Dyes in Dye-Sensitized Solar Cells

    KAUST Repository

    Hardin, Brian E.

    2010-08-11

    The energy relay dye, 4-(Dicyanomethylene)-2-methyl-6-(4- dimethylaminostyryl)-4H-pyran (DCM), was used with a near-infrared sensitizing dye, TT1, to increase the overall power conversion efficiency of a dye-sensitized solar cell (DSC) from 3.5% to 4.5%. The unattached DCM dyes exhibit an average excitation transfer efficiency (EÌ?TE) of 96% inside TT1-covered, mesostructured TiO2 films. Further performance increases were limited by the solubility of DCM in an acetonitrile based electrolyte. This demonstration shows that energy relay dyes can be efficiently implemented in optimized dye-sensitized solar cells, but also highlights the need to design highly soluble energy relay dyes with high molar extinction coefficients. © 2010 American Chemical Society.

  1. Modeling Electronic-Nuclear Interactions for Excitation Energy Transfer Processes in Light-Harvesting Complexes.

    Science.gov (United States)

    Lee, Mi Kyung; Coker, David F

    2016-08-18

    An accurate approach for computing intermolecular and intrachromophore contributions to spectral densities to describe the electronic-nuclear interactions relevant for modeling excitation energy transfer processes in light harvesting systems is presented. The approach is based on molecular dynamics (MD) calculations of classical correlation functions of long-range contributions to excitation energy fluctuations and a separate harmonic analysis and single-point gradient quantum calculations for electron-intrachromophore vibrational couplings. A simple model is also presented that enables detailed analysis of the shortcomings of standard MD-based excitation energy fluctuation correlation function approaches. The method introduced here avoids these problems, and its reliability is demonstrated in accurate predictions for bacteriochlorophyll molecules in the Fenna-Matthews-Olson pigment-protein complex, where excellent agreement with experimental spectral densities is found. This efficient approach can provide instantaneous spectral densities for treating the influence of fluctuations in environmental dissipation on fast electronic relaxation.

  2. On the modifications of near-inertial waves at fronts: implications for energy transfer across scales

    Science.gov (United States)

    Thomas, Leif N.

    2017-10-01

    In the ocean, wind-generated kinetic energy (KE) manifests itself primarily in balanced currents and near-inertial waves. The dynamics of these flows is strongly constrained by the Earth's rotation, causing the KE in balanced currents to follow an inverse cascade but also preventing wave-wave interactions from fluxing energy in the near-inertial band to lower frequencies and higher vertical wavenumbers. How wind-generated KE is transferred to small-scale turbulence and dissipated is thus a non-trivial problem. This article presents a review of recent theoretical calculations and numerical simulations that demonstrate how some surprising modifications to internal wave physics by the lateral density gradients present at ocean fronts allow for strong interactions between balanced currents and near-inertial waves that ultimately result in energy loss for both types of motion.

  3. 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...

  4. Two-Dimensional Free Energy Surfaces for Electron Transfer Reactions in Solution

    Directory of Open Access Journals (Sweden)

    Shigeo Murata

    2008-01-01

    Full Text Available Change in intermolecular distance between electron donor (D and acceptor (A can induce intermolecular electron transfer (ET even in nonpolar solvent, where solvent orientational polarization is absent. This was shown by making simple calculations of the energies of the initial and final states of ET. In the case of polar solvent, the free energies are functions of both D-A distance and solvent orientational polarization. On the basis of 2-dimensional free energy surfaces, the relation of Marcus ET and exciplex formation is discussed. The transient effect in fluorescence quenching was measured for several D-A pairs in a nonpolar solvent. The results were analyzed by assuming a distance dependence of the ET rate that is consistent with the above model.

  5. Deep Rapid Optical Follow-Up of Gravitational Wave Sources with the Dark Energy Camera

    Science.gov (United States)

    Cowperthwaite, Philip

    2018-01-01

    The detection of an electromagnetic counterpart associated with a gravitational wave detection by the Advanced LIGO and VIRGO interferometers is one of the great observational challenges of our time. The large localization regions and potentially faint counterparts require the use of wide-field, large aperture telescopes. As a result, the Dark Energy Camera, a 3.3 sq deg CCD imager on the 4-m Blanco telescope at CTIO in Chile is the most powerful instrument for this task in the Southern Hemisphere. I will report on the results from our joint program between the community and members of the dark energy survey to conduct rapid and efficient follow-up of gravitational wave sources. This includes systematic searches for optical counterparts, as well as developing an understanding of contaminating sources on timescales not normally probed by traditional untargeted supernova surveys. I will additionally comment on the immense science gains to be made by a joint detection and discuss future prospects from the standpoint of both next generation wide-field telescopes and next generation gravitational wave detectors.

  6. Activation energy of etching for CR-39 as a function of linear energy transfer of the incident particles

    CERN Document Server

    Awad, E M

    1999-01-01

    In this work, we have studied the effect of the radiation damage caused by the incident particles on the activation energy of etching for CR-39 samples. The damage produced by the incident particle is expressed in terms of the linear energy transfer (LET). CR-39 samples from American Acrylic were irradiated to three different LET particles. These are N (LET sub 2 sub 0 sub 0 = 20 KeV/mu m) as a light particle, Fe (LET sub 2 sub 0 sub 0 = 110 KeV/mu m) as a medium particle and fission fragments (ff) from a sup 2 sup 5 sup 2 Cf source as heavy particles. In general the bulk etch rate was calculated using the weight difference method and the track etch rate was determined using the track geometry at various temperatures (50-90 deg. C) and concentrations (4-9 N) of the NaOH etchant. The average activation energy E sub b related to the bulk etch rate v sub b was calculated from 1n v sub b vs. 1/T. The average activation energy E sub t related to the track etch rate v sub t was estimated from 1n v sub t vs. 1/T. It...

  7. Methods for associating or dissociating guest materials with a metal organic framework, systems for associating or dissociating guest materials within a series of metal organic frameworks, thermal energy transfer assemblies, and methods for transferring thermal energy

    Science.gov (United States)

    McGrail, B. Peter; Brown, Daryl R.; Thallapally, Praveen K.

    2014-08-05

    Methods for releasing associated guest materials from a metal organic framework are provided. Methods for associating guest materials with a metal organic framework are also provided. Methods are provided for selectively associating or dissociating guest materials with a metal organic framework. Systems for associating or dissociating guest materials within a series of metal organic frameworks are provided. Thermal energy transfer assemblies are provided. Methods for transferring thermal energy are also provided.

  8. Fundamental studies of energy-and hole/electron- transfer in hydroporphyrin architectures

    Energy Technology Data Exchange (ETDEWEB)

    Bocian, David F. [University of California, Riverside, CA (United States)

    2014-08-20

    The long-term objective of the Bocian/Holten/Lindsey research program is to design, synthesize, and characterize tetrapyrrole-based molecular architectures that absorb sunlight, funnel energy, and separate charge with high efficiency and in a manner compatible with current and future solar-energy conversion schemes. The synthetic tetrapyrroles include porphyrins and hydroporphyrins; the latter classes of molecules encompass analogues of the naturally occurring chlorophylls and bacteriochlorophylls (e.g., chlorins, bacteriochlorins, and their derivatives). The attainment of the goals of the research program requires the close interplay of molecular design and synthesis (Lindsey group), static and time-resolved optical spectroscopic measurements (Holten group), and electrochemical, electron paramagnetic resonance, and resonance Raman studies, as well as density functional theory calculations (Bocian Group). The proposed research encompasses four interrelated themes: (1) Determination of the rates of ground-state hole/electron transfer between (hydro)porphyrins in multipigment arrays as a function of array size, distance between components, linker type, site of linker connection, and frontier molecular orbital composition. (2) Examination of excited-state energy transfer among hydroporphyrins in multipigment arrrays, including both pairwise and non-adjacent transfer, with a chief aim to identify the relative contributions of through-space (Förster) and through-bond (Dexter) mechanisms of energy transfer, including the roles of site of linker connection and frontier molecular orbital composition. (3) Elucidation of the role of substituents in tuning the spectral and electronic properties of bacteriochlorins, with a primary aim of learning how to shift the long-wavelength absorption band deeper into the near-infrared region. (4) Continued development of the software package PhotochemCAD for spectral manipulations and calculations through the compilation of a database

  9. Construction of Vibronic Diabatic Hamiltonian for Excited-State Electron and Energy Transfer Processes.

    Science.gov (United States)

    Xie, Yu; Jiang, Shengshi; Zheng, Jie; Lan, Zhenggang

    2017-12-21

    Photoinduced excited-state electron and energy transfer processes are crucial in biological photoharvesting systems and organic photovoltaic devices. We discuss the construction of a diabatic vibronic Hamiltonian for the proper treatment of these processes involving the projection approach acting on both electronic wave functions and vibrational modes. In the electronic part, the wave function projection approach is used to construct the diabatic Hamiltonian in which both local excited states and charge-transfer states are included on the same footing. For the vibrational degrees of freedom, the vibronic couplings in the diabatic Hamiltonian are obtained in the basis of the pseudonormal modes localized on each monomer site by applying delocalized-to-localized mode projection. This systematic approach allows us to construct the vibronic diabatic Hamiltonian in molecular aggregates.

  10. 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.

  11. Non-linear dynamics in biological microtubules: solitons and dissipation-free energy transfer

    Science.gov (United States)

    Mavromatos, Nick E.

    2017-08-01

    I review some recent developments concerning soliton solutions in biological microtubules and their significance in transferring energy without dissipation. I discuss various types of soliton solutions, as well as ‘spikes’, of the associated non-linear Lagrange equations describing the dynamics of a ‘pseudo-spin non-linear σ-model’ that models the dynamics of a microtubule system with dipole-dipole interactions. These results will hopefully contribute to a better understanding of the functional properties of microtubules, including the motor protein dynamics and the information transfer processes. With regards to the latter we also speculate on the use of microtubules as ‘logical’ gates. Our considerations are classical, but the soliton solutions may have a microscopic quantum origin, which we briefly touch upon.

  12. Polymer-free Vertical Transfer of Silicon Nanowires and their Application to Energy Storage.

    Science.gov (United States)

    Kim, Han-Jung; Lee, Jihye; Lee, Sang Eon; Kim, Wanjung; Kim, Hwan Jin; Choi, Dae-Geun; Park, Jong Hyeok

    2013-11-01

    Silicon nanowires (SiNWs) for use as lithium-ion battery (LIB) anode materials have been studied for their one-dimensional (1D) properties and ability to accommodate large volume changes and avoid rapid capacity fading during cycling. Although the vertical transfer of SiNWs from their original substrate onto a conducting electrode is very important, to date, there has been no report of a direct integration method without polymer binders. Here, we propose for the first time a vertical transfer method for SiNWs grown on a Si substrate directly to the current-collecting electrode without using a polymer adhesive for the use as a binder-free LIB anode. The vertical SiNWs produced using a low-cost wafer-scale metal-assisted chemical etching (MaCE) process have been successfully transferred directly to a copper electrode coated with a thin Ag layer by using a simple hot pressing method. When evaluated as an LIB anode without using conventional polymeric binder and a conducting additive, the transferred vertically aligned SiNWs showed a high specific capacity (≈2150 mAh g(-1) ) and excellent rate performance. It is believed that the anode-manufacturing process is simple and fast, thus enabling a large-scale production that is of low-cost, broadly applicable, and provides new avenues for the rational engineering of Si-based electrode materials with enhanced power density and conductivity. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. The microscopic interaction parameters for Er{sup 3+}/Ho{sup 3+} energy transfer in tellurite glasses

    Energy Technology Data Exchange (ETDEWEB)

    Li Xujie [College of Computer Science and Engineering, Wenzhou University Zhejiang 325035 (China); Faculty of Information Science and Engineering, State Key Laboratory Base of Novel Functional Materials and Preparation Science, Ningbo University Zhejiang 315211 (China)], E-mail: lixujie101@yahoo.com.cn; Zhang Wenjie [College of Computer Science and Engineering, Wenzhou University Zhejiang 325035 (China)

    2008-08-01

    We investigate the energy transfer between Er{sup 3+}/Ho{sup 3+} in tellurite glasses. The main channels of energy transfer between Er{sup 3+}/Ho{sup 3+} are analyzed in detail. The microscopic interaction parameters of resonant and non-resonant (phonon-assisted) energy transfer parameters via Er{sup 3+}{yields}Ho{sup 3+} are calculated. The result shows that the resonant energy transfers Er{sup 3+}({sup 2}H{sub 11/2}({sup 4}S{sub 3/2})){yields}Ho{sup 3+}({sup 5}F{sub 4}({sup 5}S{sub 2})) and Er{sup 3+}({sup 4}F{sub 9/2}){yields}Ho{sup 3+}({sup 5}F{sub 5}) are very efficient and non-resonant energy transfers Er{sup 3+}({sup 4}I{sub 13/2}){yields}Ho{sup 3+}({sup 5}I{sub 7}) and Er{sup 3+}({sup 4}I{sub 11/2}){yields}Ho{sup 3+}({sup 5}I{sub 6}), which are a phonon-assisted energy transfer process because of energy mismatch are also existed and cannot be neglected.

  14. Enhancement of Energy Production of the Intervertebral Disc by the Implantation of Polyurethane Mass Transfer Devices.

    Science.gov (United States)

    Wang, Yu-Fu; Levene, Howard B; Gu, Weiyong; Huang, C -Y Charles

    2017-06-13

    Insufficient nutrient supply has been suggested to be one of the etiologies for intervertebral disc (IVD) degeneration. We are investigating nutrient transport into the IVD as a potential treatment strategy for disc degeneration. Most cellular activities in the IVD (e.g., cell proliferation and extracellular matrix production) are mainly driven by adenosine-5'-triphosphate (ATP) which is the main energy currency. The objective of this study was to investigate the effect of increased mass transfer on ATP production in the IVD by the implantation of polyurethane (PU) mass transfer devices. In this study, the porcine functional spine units were used and divided into intact, device and surgical groups. For the device and surgical groups, two puncture holes were created bilaterally at the dorsal side of the annulus fibrosus (AF) region and the PU mass transfer devices were only implanted into the holes in the device group. Surgical groups were observed for the effects of placing the holes through the AF only. After 7 days of culture, the surgical group exhibited a significant reduction in the compressive stiffness and disc height compared to the intact and device groups, whereas no significant differences were found in compressive stiffness, disc height and cell viability between the intact and device groups. ATP, lactate and the proteoglycan contents in the device group were significantly higher than the intact group. These results indicated that the implantation of the PU mass transfer device can promote the nutrient transport and enhance energy production without compromising mechanical and cellular functions in the disc. These results also suggested that compromise to the AF has a negative impact on the IVD and must be addressed when treatment strategies are considered. The results of this study will help guide the development of potential strategies for disc degeneration.

  15. 78 FR 57375 - Toutant Hydro Power, Inc.; Energy System, LLC.; Notice of Application for Transfer of License...

    Science.gov (United States)

    2013-09-18

    ... Transfer of License, and Soliciting Comments and Motions To Intervene On September 6, 2013, Toutant Hydro Power, Inc. (transferor) and Energy System, LLC (transferee) filed an application for transfer of license for the M.S.C. Power Project, FERC No. 5679, located on the Quinebaug River in Windham County...

  16. Boiling/evaporative heat transfer from spheres in packed-bed thermal energy storage units

    Science.gov (United States)

    Arimilli, R. V.; Moy, C. A.

    1990-05-01

    An experimental study was conducted to study boiling/evaporative heat transfer from heated spheres in vertical packed beds with downward liquid vapor flow of Refrigerant-113. Surface superheats of 1 to 50 C; mass flow rates of 1.7, 2.7, and 5.6 kg/min; sphere diameters of 1.59 and 2.54 cm; quality (i.e., mass fraction of vapor) of the inlet flow of 2 to 100 percent; and two surface roughness conditions were considered. To determine heat transfer coefficients, smooth and roughened aluminum spheres of the same diameter as the other spheres in the bed were instrumented with two thermocouples each for measuring the surface temperatures and a tiny electrical resistance heater for input power. The heat transfer measurements were made under steady-state conditions. Heat transfer coefficients were independently determined for each sphere at three values of surface superheat. The quantitative results are represented as a correlation for the boiling heat transfer coefficients in terms of a homogeneous model. The equation correlates very effectively with the dimensionless temperature difference. The correlation may be used in the development of numerical models to simulate the transient thermal performance of a packed-bed thermal energy storage unit while operating as an evaporator. The boiling of the liquid vapor flow around the spheres in the packed bed was visually observed with a fiber optic boroscope and recorded on a video tape. The visualization results showed qualitatively the presence of our four distinct flow regimes. One of these occurs under subcooled regime. The other three occur under saturated inlet conditions and are referred to as the low-quality, medium-quality, and high-quality regimes. The regimes are discussed in detail.

  17. Excited state conformational dynamics in carotenoids: dark intermediates and excitation energy transfer.

    Science.gov (United States)

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

    2015-04-15

    A consideration of the excited state potential energy surfaces of carotenoids develops a new hypothesis for the nature of the conformational motions that follow optical preparation of the S2 (1(1)Bu(+)) state. After an initial displacement from the Franck-Condon geometry along bond length alternation coordinates, it is suggested that carotenoids pass over a transition-state barrier leading to twisted conformations. This hypothesis leads to assignments for several dark intermediate states encountered in femtosecond spectroscopic studies. The Sx state is assigned to the structure reached upon the onset of torsional motions near the transition state barrier that divides planar and twisted structures on the S2 state potential energy surface. The X state, detected recently in two-dimensional electronic spectra, corresponds to a twisted structure well past the barrier and approaching the S2 state torsional minimum. Lastly, the S(∗) state is assigned to a low lying S1 state structure with intramolecular charge transfer character (ICT) and a pyramidal conformation. It follows that the bent and twisted structures of carotenoids that are found in photosynthetic light-harvesting proteins yield excited-state structures that favor the development of an ICT character and optimized energy transfer yields to (bacterio)chlorophyll acceptors. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Ultrafast energy transfer in oligofluorene-aluminum bis(8-hydroxyquinoline)acetylacetone coordination polymers.

    Science.gov (United States)

    Montes, Victor A; Zyryanov, Grigory V; Danilov, Evgeny; Agarwal, Neeraj; Palacios, Manuel A; Anzenbacher, Pavel

    2009-02-11

    Understanding the excited-state dynamics in conjugated systems can lead to their better utilization in optical sensors, organic photovoltaics (OPVs), and organic light-emitting diodes (OLEDs). We present the synthesis of self-assembled coordination polymers comprising two types of fluorescent moieties: discrete fluorene oligomers of a well-defined length (n = 1-9) connected via aluminum(III) bis(8-quinolinolate)acetylacetone joints. Due to their well-defined structure, these materials allowed for a detailed study of energy migration processes within the materials. Thus, femtosecond transient spectroscopy was used to study the ultrafast energy transfer from the oligofluorene to the quinolinolate moieties, which was found to proceed at a rate of 10(11) s(-1). The experimental results were found to be in agreement with the behavior predicted according to the Beljonne's improved Forster model of energy transfer. In addition, the solid-state and semiconductor properties of these coordination polymers allowed for the fabrication of OLEDs. Preliminary experiments with simple two- and three-layer devices fabricated by spin-coating yield bright yellow electroluminescence with maximum brightness of 6000 cd/m(2), with a turn-on voltage of approximately 6 V and a maximum external quantum efficiency of up to 1.2%, suggesting their potential for use in PLED applications.

  19. Localized surface plasmon mediated energy transfer in the vicinity of core-shell nanoparticle

    Energy Technology Data Exchange (ETDEWEB)

    Shishodia, Manmohan Singh, E-mail: manmohan@gbu.ac.in; Juneja, Soniya [Department of Applied Physics, School of Vocational Studies and Applied Sciences, Gautam Buddha University, Greater Noida 201308 (India)

    2016-05-28

    Multipole spectral expansion based theory of energy transfer interactions between a donor and an acceptor molecule in the vicinity of a core-shell (nanoshell or core@shell) based plasmonic nanostructure is developed. In view of the diverse applications and rich plasmonic features such as tuning capability of surface plasmon (SP) frequencies, greater sensitivity to the change of dielectric environment, controllable redirection of electromagnetic radiation, closed form expressions for Energy Transfer Rate Enhancement Factor (ETREF) near core-shell particle are reported. The dependence of ETREF on different parameters is established through fitting equations, perceived to be of key importance for developing appropriate designs. The theoretical approach developed in the present work is capable of treating higher order multipoles, which, in turn, are also shown to play a crucial role in the present context. Moreover, closed form expressions derived in the present work can directly be used as formula, e.g., for designing SP based biosensors and estimating energy exchange between proteins and excitonic interactions in quantum dots.

  20. Energy transfer mechanisms in heavy metal oxide glasses doped with lanthanide ions

    Science.gov (United States)

    Ragin, Tomasz; Zmojda, Jacek; Kochanowicz, Marcin; Miluski, Piotr; Dorosz, Dominik

    2016-09-01

    In this paper, glasses based on bismuth, germanium, gallium and sodium oxides have been synthesized in terms of low phonon energy (724 cm-1) and high thermal stability (ΔT = 127°C). Synthesis process have been optimized using low vacuum conditions (approx. 60 mBar) to improve the transmittance in the mid-infrared region and decrease the content of hydroxide groups in the material structure. Glass doped with erbium ions has been pumped with high power diode (λexc = 980 nm) to obtain luminescence in the band of 2.7 μm as a result of Er3+: 4I11/2 -> 4I13/2 radiative transition. For analysis of emission properties and energy transfer mechanisms, glasses co-doped with Er3+/Ho3+, Er3+/Pr3+, Er3+/Nd3+ ions have been synthesized. Obtained results indicated energy transfer phenomenon between lanthanide ions and elements forming the glass matrix. This demonstrates that developed heavy metal oxide glass doped with optimal rare earth elements system is an attractive material for mid-infrared applications.

  1. 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.

  2. Optical Energy Transfer Mechanisms: From Naphthalene to Biacetyl in Liquids and from Pyrazine to Biacetyl

    Directory of Open Access Journals (Sweden)

    Fuat Bayrakceken

    2012-01-01

    Full Text Available Optical energy transfer from naphthalene to biacetyl in liquids at room temperature is studied. Electronically excited naphthalene with 200–260 nm ultraviolet (UV light emits photons in its emission band and the emitted photons are absorbed by biacetyl, which, in turn, excites biacetyl phosphorescence. The resulting phosphorescence is very stable with emission peak at 545 nm for different excitation wavelengths from 200 to 260 nm. Similar optical energy transfer is also observed from pyrazine to biacetyl. The sensitization of biacetyl by several aromatic donors has been investigated in detail. An aromatic donor, pyrazine, is raised to its first excited singlet state by absorption of ultraviolet radiation. Excitation wavelengths were selected in the first - band of pyrazine. Intersystem crossing in pyrazine is sufficiently fast to give a triplet yield of almost unity as determined by the biacetyl method. The optical excess energy in the biacetyl will be released as light, which is sensitized fluorescence. Biacetyl is the simplest molecule among a wide range of -dicarbonyl compounds, which is important for photophysics and photochemistry applications.

  3. Energy transfer in nanowire solar cells with photon-harvesting shells

    KAUST Repository

    Peters, C. H.

    2009-01-01

    The concept of a nanowire solar cell with photon-harvesting shells is presented. In this architecture, organic molecules which absorb strongly in the near infrared where silicon absorbs weakly are coupled to silicon nanowires (SiNWs). This enables an array of 7-μm -long nanowires with a diameter of 50 nm to absorb over 85% of the photons above the bandgap of silicon. The organic molecules are bonded to the surface of the SiNWs forming a thin shell. They absorb the low-energy photons and subsequently transfer the energy to the SiNWs via Förster resonant energy transfer, creating free electrons and holes within the SiNWs. The carriers are then separated at a radial p-n junction in a nanowire and extracted at the respective electrodes. The shortness of the nanowires is expected to lower the dark current due to the decrease in p-n junction surface area, which scales linearly with wire length. The theoretical power conversion efficiency is 15%. To demonstrate this concept, we measure a 60% increase in photocurrent from a planar silicon-on-insulator diode when a 5 nm layer of poly[2-methoxy-5-(2′ -ethyl-hexyloxy)-1,4-phenylene vinylene is applied to the surface of the silicon. This increase is in excellent agreement with theoretical predictions. © 2009 American Institute of Physics.

  4. Energy Transfer Highway in Nd3+-Sensitized Nanoparticles for Efficient near-Infrared Bioimaging.

    Science.gov (United States)

    Cao, Cong; Xue, Meng; Zhu, Xingjun; Yang, Pengyuan; Feng, Wei; Li, Fuyou

    2017-06-07

    Despite the large absorption cross-section of Nd3+ dopant as a sensitizer in lanthanide doped luminescence system, the strong cross-relaxation effect of it impedes the promotion of doping concentration and thus reduces the utilization of excitation light. In this work, we introduce a highly efficient acceptor, Yb3+ ion, which can quickly receive energy from Nd3+ ions, to construct an energy transfer highway for the enhancement of near-infrared emission. By using the energy transfer highway, the doping amount of Nd3+ ions in our NaYF4:Yb,Nd@CaF2 core/shell nanoparticles (CSNPs) can be markedly elevated to 60%. The quantum yield of CSNPs was determined to be 20.7%, which provides strong near-infrared luminescence for further bioimaging application. Remarkably, deep tissue penetration depth (∼10 mm) in in vitro imaging and high spatial resolution of blood vessel (∼0.19 mm) in in vivo imaging were detected clearly with weak autofluorescence, demonstrating that probes can be used as excellent NIR biosensors.

  5. Changes in the mitochondrial function and in the efficiency of energy transfer pathways during cardiomyocyte aging.

    Science.gov (United States)

    Tepp, Kersti; Puurand, Marju; Timohhina, Natalja; Adamson, Jasper; Klepinin, Aleksandr; Truu, Laura; Shevchuk, Igor; Chekulayev, Vladimir; Kaambre, Tuuli

    2017-08-01

    The role of mitochondria in alterations that take place in the muscle cell during healthy aging is a matter of debate during recent years. Most of the studies in bioenergetics have a focus on the model of isolated mitochondria, while changes in the crosstalk between working myofibrils and mitochondria in senescent cardiomyocytes have been less studied. The aim of our research was to investigate the modifications in the highly regulated ATP production and energy transfer systems in heart cells in old rat cardiomyocytes. The results of our work demonstrated alterations in the diffusion restrictions of energy metabolites, manifested by changes in the apparent Michaelis-Menten constant of mitochondria to exogenous ADP. The creatine kinase (CK) phosphotransfer pathway efficiency declines significantly in senescence. The ability of creatine to stimulate OXPHOS as well as to increase the affinity of mitochondria for ADP is falling and the most critical decline is already in the 1-year group (middle-age model in rats). Also, a moderate decrease in the adenylate kinase phosphotransfer system was detected. The importance of glycolysis increases in senescence, while the hexokinase activity does not change during healthy aging. The main result of our study is that the decline in the heart muscle performance is not caused by the changes in the respiratory chain complexes activity but mainly by the decrease in the energy transfer efficiency, especially by the CK pathway.

  6. 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...

  7. 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...

  8. Experimental measurements of energy transfer and nonlinear interaction in turbulence at the sino-united spherical tokamak

    Science.gov (United States)

    Chai, Song; Xu, Yuhong; Gao, Zhe; Wang, Wenhao; Liu, Yangqing; Tan, Yi

    2017-03-01

    The characteristics of the energy transfer and nonlinear coupling among edge electromagnetic turbulence have been dedicatedly studied in various discharge stages at the sino-united spherical tokamak using multiple Langmuir and magnetic probe arrays. The wavelet bispectral analysis and the modified Kim's method are applied to investigate turbulence properties and their linear growth/damping and nonlinear energy transfer rates, along with multi-field turbulence interactions. The results show diverse features in the linear growth and nonlinear energy transfer between multi-field fluctuations during the current ramp-up, stationary, and internal connection event discharge phases. The diversity implies the importance to develop more sophisticated multi-field models to directly estimate the energy transfer rate among multiple turbulent fields.

  9. 40 CFR 74.48 - Transfer of allowances from the replacement of thermal energy-process sources. [Reserved

    Science.gov (United States)

    2010-07-01

    ... replacement of thermal energy-process sources. 74.48 Section 74.48 Protection of Environment ENVIRONMENTAL... and End of Year Compliance § 74.48 Transfer of allowances from the replacement of thermal energy—process sources. ...

  10. Comparison of calculated and experimentally resolved rate constants for excitation energy transfer in C-phycocyanin. 1. Monomers

    Energy Technology Data Exchange (ETDEWEB)

    Debreczeny, M.P.; Sauer, K. [Lawrence Berkeley Lab., CA (United States); Zhou, J.; Bryant, D.A. [Pennsylvania State Univ., University Park, PA (United States)

    1995-05-18

    Rate constants for excitation energy transfer in light-harvesting protein, C-phycocyanin (PC), in the monomeric aggregation state, isolated from the cyanobacterium cynechococcus sp. PCC 7002, are calculated, using Foerster theory and compared with the results of time-resolved fluorescence measurements. The assignments of the energy-transfer rate constants in PC monomers are confirmed here by time-resolved fluorescence anisotropy measurements of the PC monomers isolated from both the wild-type and a mutant strain (cpcB/C155S) whose PC is missing the {beta}{sub 155} chromophore. It is concluded that the Foerster model of resonant energy transfer in the weak coupling limit successfully describes the dominant energy-transfer processes in this protein in the monomeric state. 31 refs., 3 figs., 4 tabs.

  11. Energy transfer dynamics in trimers and aggregates of light-harvesting complex II probed by 2D electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Enriquez, Miriam M.; Zhang, Cheng; Tan, Howe-Siang, E-mail: howesiang@ntu.edu.sg [Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore); Akhtar, Parveen; Garab, Győző; Lambrev, Petar H., E-mail: lambrev@brc.hu [Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, P.O. Box 521, H-6701 Szeged (Hungary)

    2015-06-07

    The pathways and dynamics of excitation energy transfer between the chlorophyll (Chl) domains in solubilized trimeric and aggregated light-harvesting complex II (LHCII) are examined using two-dimensional electronic spectroscopy (2DES). The LHCII trimers and aggregates exhibit the unquenched and quenched excitonic states of Chl a, respectively. 2DES allows direct correlation of excitation and emission energies of coupled states over population time delays, hence enabling mapping of the energy flow between Chls. By the excitation of the entire Chl b Q{sub y} band, energy transfer from Chl b to Chl a states is monitored in the LHCII trimers and aggregates. Global analysis of the two-dimensional (2D) spectra reveals that energy transfer from Chl b to Chl a occurs on fast and slow time scales of 240–270 fs and 2.8 ps for both forms of LHCII. 2D decay-associated spectra resulting from the global analysis identify the correlation between Chl states involved in the energy transfer and decay at a given lifetime. The contribution of singlet–singlet annihilation on the kinetics of Chl energy transfer and decay is also modelled and discussed. The results show a marked change in the energy transfer kinetics in the time range of a few picoseconds. Owing to slow energy equilibration processes, long-lived intermediate Chl a states are present in solubilized trimers, while in aggregates, the population decay of these excited states is significantly accelerated, suggesting that, overall, the energy transfer within the LHCII complexes is faster in the aggregated state.

  12. Photoluminescence and energy transfer studies of Dy(3+)-doped fluorophosphate glasses.

    Science.gov (United States)

    Praveena, R; Vijaya, R; Jayasankar, C K

    2008-08-01

    Dy(3+)-doped fluorophosphate glasses with composition (in mol%) (56-x/2)P(2)O(5)+17K(2)O+(15-x/2)BaO+8Al(2)O(3) + 4AlF(3)+ xDy(2)O(3), x=0.01, 0.05, 0.1, 1.0 and 2.0, have been prepared by melt quenching technique. The luminescence spectra and lifetimes of (4)F(9/2) level of Dy(3+) ions in these glasses have been measured using the 457.9 nm line of argon ion laser as an excitation source. The free-ion calculation and Judd-Ofelt analysis have been performed. The room temperature emission spectra corresponding to (4)F(9/2)-->(6)H(J) (J=7/2, 9/2, 11/2, 13/2 and 15/2) transitions of Dy(3+) ions were measured. The fluorescence decay from (4)F(9/2) level have been measured by monitoring the intense (4)F(9/2)-->(6)H(13/2) transition. The lifetime of the decay is obtained by taking the first e-folding times of the decay curves and is found to decrease with increase in Dy(3+) ions concentration due to concentration quenching. The decay curves are found to be perfectly single exponential for samples with low Dy(3+) ion concentration. The non-exponential decay curves observed for higher concentrations are well fitted to the Inokuti-Hirayama model for S=6, which indicates that the energy transfer between the donor and acceptor is of dipole-dipole nature. The energy transfer parameter and donor to acceptor interaction increases with Dy(3+) ions concentration due to increase of energy transfer from Dy(3+) (donor) to unexcited Dy(3+) (acceptor) ions.

  13. Electronic excitation energy transfer and nonstationary processes in KH2PO4:Tl crystals

    Science.gov (United States)

    Ogorodnikov, I. N.; Pustovarov, V. A.

    2017-04-01

    We report the results of our experimental study and numerical simulation of the electronic excitation energy transfer to impurity centers under conditions where nonstationary processes take place in the hydrogen sublattice of potassium dihydrogen phosphate (KH2PO4) single crystals doped with mercury-like Tl+ ions (KDP:Tl). We present the experimental results of our investigation of the decay kinetics of the transient optical absorption (100 ns-50 s) of intrinsic defects in the hydrogen sublattice of KDP:Tl obtained by pulsed absorption spectroscopy and the results of our study of the dynamics of the change in steady-state luminescence intensity with irradiation time (1-5000 s). To explain the transfer of the energy being released during electron recombination involving intrinsic KDP:Tl lattice defects, we formulate a mathematical model for the transfer of this energy to impurity Tl+ luminescence centers. Within the model being developed, we present the systems of differential balance equations describing the nonstationary processes in the electron subsystem and the hydrogen sublattice; provide a technique for calculating the pair correlation functions Y( r, t) of dissimilar defects based on the solution of the Smoluchowski equation for the system of mobile hydrogen sublattice defects; calculate the time-dependent reaction rate constants K( t) for various experimental conditions; and outline the peculiarities and results of the model parametrization based on our experimental data. Based on our investigation, the dramatic and significant effect of a gradual inertial increase by a factor of 50-100 in steady-state luminescence intensity in the 4.5-eV band in KDP:Tl crystals due to the luminescence of mercury-like Tl+ ions has been explained qualitatively and quantitatively.

  14. On the ultrafast kinetics of the energy and electron transfer reactions in photosystem I

    Energy Technology Data Exchange (ETDEWEB)

    Slavov, Chavdar Lyubomirov

    2009-07-09

    The subject of the current work is one of the main participants in the light-dependent phase of oxygenic photosynthesis, Photosystem I (PS I). This complex carries an immense number of cofactors: chlorophylls (Chl), carotenoids, quinones, etc, which together with the protein entity exhibit several exceptional properties. First, PS I has an ultrafast light energy trapping kinetics with a nearly 100% quantum efficiency. Secondly, both of the electron transfer branches in the reaction center are suggested to be active. Thirdly, there are some so called 'red' Chls in the antenna system of PS I, absorbing light with longer wavelengths than the reaction center. These 'red' Chls significantly modify the trapping kinetics of PS I. The purpose of this thesis is to obtain better understanding of the above-mentioned, specific features of PS I. This will not merely cast more light on the mechanisms of energy and electron transfer in the complex, but also will contribute to the future developments of optimized artificial light-harvesting systems. In the current work, a number of PS I complexes isolated from different organisms (Thermosynechococcus elongatus, Chlamydomonas reinhardtii, Arabidopsis thaliana) and possessing distinctive features (different macroorganisation, monomers, trimers, monomers with a semibelt of peripheral antenna attached; presence of 'red' Chls) is investigated. The studies are primarily focused on the electron transfer kinetics in each of the cofactor branches in the PS I reaction center, as well as on the effect of the antenna size and the presence of 'red' Chls on the trapping kinetics of PS I. These aspects are explored with the help of several ultrafast optical spectroscopy methods: (i) time-resolved fluorescence ? single photon counting and synchroscan streak camera; and (ii) ultrafast transient absorption. Physically meaningful information about the molecular mechanisms of the energy trapping in PS I is

  15. Strategies to enhance the excitation energy-transfer efficiency in a light-harvesting system using the intra-molecular charge transfer character of carotenoids

    Energy Technology Data Exchange (ETDEWEB)

    Yukihira, Nao [Department of Applied Chemistry for Environment; School of Science and Technology; Kwansei Gakuin University; Sanda; Japan; Sugai, Yuko [Department of Applied Chemistry for Environment; School of Science and Technology; Kwansei Gakuin University; Sanda; Japan; Fujiwara, Masazumi [Department of Applied Chemistry for Environment; School of Science and Technology; Kwansei Gakuin University; Sanda; Japan; Kosumi, Daisuke [Institute of Pulsed Power Science; Kumamoto University; Kumamoto; Japan; Iha, Masahiko [South Product Co. Ltd.; Uruma-shi; Japan; Sakaguchi, Kazuhiko [Department of Chemistry; Graduate School of Science; Osaka City University; Osaka 558-8585; Japan; Katsumura, Shigeo [Department of Chemistry; Graduate School of Science; Osaka City University; Osaka 558-8585; Japan; Gardiner, Alastair T. [Glasgow Biomedical Research Centre; University of Glasgow; 126 University Place; Glasgow, G12 8QQ; UK; Cogdell, Richard J. [Glasgow Biomedical Research Centre; University of Glasgow; 126 University Place; Glasgow, G12 8QQ; UK; Hashimoto, Hideki [Department of Applied Chemistry for Environment; School of Science and Technology; Kwansei Gakuin University; Sanda; Japan

    2017-01-01

    Fucoxanthin is a carotenoid that is mainly found in light-harvesting complexes from brown algae and diatoms. Due to the presence of a carbonyl group attached to polyene chains in polar environments, excitation produces an excited intra-molecular charge transfer. This intra-molecular charge transfer state plays a key role in the highly efficient (~95%) energy-transfer from fucoxanthin to chlorophyllain the light-harvesting complexes from brown algae. In purple bacterial light-harvesting systems the efficiency of excitation energy-transfer from carotenoids to bacteriochlorophylls depends on the extent of conjugation of the carotenoids. In this study we were successful, for the first time, in incorporating fucoxanthin into a light-harvesting complex 1 from the purple photosynthetic bacterium,Rhodospirillum rubrumG9+ (a carotenoidless strain). Femtosecond pump-probe spectroscopy was applied to this reconstituted light-harvesting complex in order to determine the efficiency of excitation energy-transfer from fucoxanthin to bacteriochlorophyllawhen they are bound to the light-harvesting 1 apo-proteins.

  16. Surface charges and J H Poynting’s disquisitions on energy transfer in electrical circuits

    Science.gov (United States)

    Matar, M.; Welti, R.

    2017-11-01

    In this paper we review applications given by J H Poynting (1884) on the transfer of electromagnetic energy in DC circuits. These examples were strongly criticized by O Heaviside (1887). Heaviside stated that Poynting had a misconception about the nature of the electric field in the vicinity of a wire through which a current flows. The historical review of this conflict and its resolution based on the consideration of electrical charges on the surface of the wires can be useful for student courses on electromagnetism or circuit theory.

  17. Energy transfer from conjugated polymer to bacterial light-harvesting complex

    Science.gov (United States)

    Buczynska, D.; Bujak, Ł.; Loi, M. A.; Brotosudarmo, T. H. P.; Cogdell, R.; Mackowski, S.

    2012-10-01

    Energy transfer from a conjugated polymer blend (poly(9,9-dioctylfluorenyl-2,7-diyl):poly (2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene) to a light-harvesting complex 2 from purple bacteria has been demonstrated using time-resolved fluorescence spectroscopy. For our hybrid nanostructure, we observe a 30% reduction of the fluorescence lifetime of the polymer emission as compared to the pure polymer layer. This result is an important step towards integrating naturally evolved biomolecules with synthetic materials into biohybrid organic electronic systems.

  18. Rectifier Design Challenges for RF Wireless Power Transfer and Energy Harvesting Systems

    Directory of Open Access Journals (Sweden)

    A. Collado

    2017-06-01

    Full Text Available The design of wireless power transfer (WPT and energy harvesting (EH solutions poses different challenges towards achieving maximum RF-DC conversion efficiency in these systems. This paper covers several selected challenges when developing WPT and electromagnetic EH solutions, such as the design of multiband and broadband rectifiers, the minimization of the effect that load and input power variations may have on the system performance and finally the most optimum power combining mechanisms that can be used when dealing with multi-element rectifiers.

  19. 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....

  20. Understanding and modeling Förster-type resonance energy transfer (FRET)

    CERN Document Server

    Hernández Martínez, Pedro Ludwig; Demir, Hilmi Volkan

    2017-01-01

    This Brief presents a complete study of the generalized theory of Förster-type energy transfer in nanostructures with mixed dimensionality. Here the aim is to obtain a generalized theory of FRET including a comprehensive set of analytical equations for all combinations and configurations of nanostructures and deriving generic expressions for the dimensionality involved. In this brief, the modification of FRET mechanism with respect to the nanostructure serving as the donor vs. the acceptor will be included, focusing on the rate’s distance dependency and the role of the effective dielectric function in FRET, which will be a unique, useful source for those who study and model FRET.

  1. Energy Efficiency Maximization for WSNs with Simultaneous Wireless Information and Power Transfer.

    Science.gov (United States)

    Yu, Hongyan; Zhang, Yongqiang; Guo, Songtao; Yang, Yuanyuan; Ji, Luyue

    2017-08-18

    Recently, the simultaneous wireless information and power transfer (SWIPT) technique has been regarded as a promising approach to enhance performance of wireless sensor networks with limited energy supply. However, from a green communication perspective, energy efficiency optimization for SWIPT system design has not been investigated in Wireless Rechargeable Sensor Networks (WRSNs). In this paper, we consider the tradeoffs between energy efficiency and three factors including spectral efficiency, the transmit power and outage target rate for two different modes, i.e., power splitting (PS) and time switching modes (TS), at the receiver. Moreover, we formulate the energy efficiency maximization problem subject to the constraints of minimum Quality of Service (QoS), minimum harvested energy and maximum transmission power as non-convex optimization problem. In particular, we focus on optimizing power control and power allocation policy in PS and TS modes to maximize energy efficiency of data transmission. For PS and TS modes, we propose the corresponding algorithm to characterize a non-convex optimization problem that takes into account the circuit power consumption and the harvested energy. By exploiting nonlinear fractional programming and Lagrangian dual decomposition, we propose suboptimal iterative algorithms to obtain the solutions of non-convex optimization problems. Furthermore, we derive the outage probability and effective throughput from the scenarios that the transmitter does not or partially know the channel state information (CSI) of the receiver. Simulation results illustrate that the proposed optimal iterative algorithm can achieve optimal solutions within a small number of iterations and various tradeoffs between energy efficiency and spectral efficiency, transmit power and outage target rate, respectively.

  2. Energy Efficiency Maximization for WSNs with Simultaneous Wireless Information and Power Transfer

    Science.gov (United States)

    Yu, Hongyan; Zhang, Yongqiang; Yang, Yuanyuan; Ji, Luyue

    2017-01-01

    Recently, the simultaneous wireless information and power transfer (SWIPT) technique has been regarded as a promising approach to enhance performance of wireless sensor networks with limited energy supply. However, from a green communication perspective, energy efficiency optimization for SWIPT system design has not been investigated in Wireless Rechargeable Sensor Networks (WRSNs). In this paper, we consider the tradeoffs between energy efficiency and three factors including spectral efficiency, the transmit power and outage target rate for two different modes, i.e., power splitting (PS) and time switching modes (TS), at the receiver. Moreover, we formulate the energy efficiency maximization problem subject to the constraints of minimum Quality of Service (QoS), minimum harvested energy and maximum transmission power as non-convex optimization problem. In particular, we focus on optimizing power control and power allocation policy in PS and TS modes to maximize energy efficiency of data transmission. For PS and TS modes, we propose the corresponding algorithm to characterize a non-convex optimization problem that takes into account the circuit power consumption and the harvested energy. By exploiting nonlinear fractional programming and Lagrangian dual decomposition, we propose suboptimal iterative algorithms to obtain the solutions of non-convex optimization problems. Furthermore, we derive the outage probability and effective throughput from the scenarios that the transmitter does not or partially know the channel state information (CSI) of the receiver. Simulation results illustrate that the proposed optimal iterative algorithm can achieve optimal solutions within a small number of iterations and various tradeoffs between energy efficiency and spectral efficiency, transmit power and outage target rate, respectively. PMID:28820496

  3. A novel photoinduced electron transfer (PET) primer technique for rapid real-time PCR detection of Cryptosporidium spp

    Energy Technology Data Exchange (ETDEWEB)

    Jothikumar, N., E-mail: jin2@cdc.gov; Hill, Vincent R.

    2013-06-28

    Highlights: •Uses a single-labeled fluorescent primer for real-time PCR. •The detection sensitivity of PET PCR was comparable to TaqMan PCR. •Melt curve analysis can be performed to confirm target amplicon production. •Conventional PCR primers can be converted to PET PCR primers. -- Abstract: We report the development of a fluorescently labeled oligonucleotide primer that can be used to monitor real-time PCR. The primer has two parts, the 3′-end of the primer is complimentary to the target and a universal 17-mer stem loop at the 5′-end forms a hairpin structure. A fluorescent dye is attached to 5′-end of either the forward or reverse primer. The presence of guanosine residues at the first and second position of the 3′ dangling end effectively quenches the fluorescence due to the photo electron transfer (PET) mechanism. During the synthesis of nucleic acid, the hairpin structure is linearized and the fluorescence of the incorporated primer increases several-fold due to release of the fluorescently labeled tail and the absence of guanosine quenching. As amplicons are synthesized during nucleic acid amplification, the fluorescence increase in the reaction mixture can be measured with commercially available real-time PCR instruments. In addition, a melting procedure can be performed to denature the double-stranded amplicons, thereby generating fluorescence peaks that can differentiate primer dimers and other non-specific amplicons if formed during the reaction. We demonstrated the application of PET-PCR for the rapid detection and quantification of Cryptosporidium parvum DNA. Comparison with a previously published TaqMan® assay demonstrated that the two real-time PCR assays exhibited similar sensitivity for a dynamic range of detection of 6000–0.6 oocysts per reaction. PET PCR primers are simple to design and less-expensive than dual-labeled probe PCR methods, and should be of interest for use by laboratories operating in resource

  4. Characterizing the Performance of a Proton-Transfer-Reaction Mass Spectrometer with a Rapid Cycling Tenax Preconcentrator

    Energy Technology Data Exchange (ETDEWEB)

    Garland, S.P.; Alexander, M.L.

    2006-01-01

    Volatile organic compounds (VOCs) are species of interest for atmospheric modeling, worker chemical exposure and medical studies. Sometimes the required detection limits for these compounds is below the capability of existing real-time instrumentation. Preconcentrators have been implemented as an inexpensive way to amplify chemical signals and improve detection limits. Proton-transfer-reaction mass spectrometry (PTR-MS) has been used as a tool for studying low concentrations of VOCs, but it lacks the capability to differentiate chemical signal contributions from isobaric compounds. In this work, behavior of a newly designed Tenax TA preconcentrator when coupled with a PTRMS is characterized. This novel preconcentrator design allows rapid temperature cycling, maintaining near real-time response. The preconcentrator was exposed to a sample gas of toluene in varying concentrations and loading times between and then thermally desorbed for analysis by PTR-MS. The effects of preconcentrating multiple analytes simultaneously were also investigated as well as the chromatographic effects of the preconcentrator. A linear behavior was observed when the integrated ion count rates (ICPS) from thermal desorption peaks were regressed against both varying loading times at a constant toluene concentration and varying concentrations with constant loading times. From these trends, it is possible to determine the concentration of a VOC by knowing its ICPS from thermal desorption peaks from a known preconcentration time. Peak height ion count rates representing ultimate detectability were amplified by factors up to 257 times the original signal, extending the range of the PTR-MS from 50pptv to nearly 250 parts per quadrillion. This corresponds to an ultimate sensitivity of 200 parts per quadrillion with 20 minute time resolution. Quantitative preconcentrator behavior was demonstrated using ICPS from these ion peaks and were amplified as much as 148 times their original signal. Results

  5. Vibronic coupling explains the ultrafast carotenoid-to-bacteriochlorophyll energy transfer in natural and artificial light harvesters

    Science.gov (United States)

    Perlík, Václav; Seibt, Joachim; Cranston, Laura J.; Cogdell, Richard J.; Lincoln, Craig N.; Savolainen, Janne; Šanda, František; Mančal, Tomáš; Hauer, Jürgen

    2015-06-01

    The initial energy transfer steps in photosynthesis occur on ultrafast timescales. We analyze the carotenoid to bacteriochlorophyll energy transfer in LH2 Marichromatium purpuratum as well as in an artificial light-harvesting dyad system by using transient grating and two-dimensional electronic spectroscopy with 10 fs time resolution. We find that Förster-type models reproduce the experimentally observed 60 fs transfer times, but overestimate coupling constants, which lead to a disagreement with both linear absorption and electronic 2D-spectra. We show that a vibronic model, which treats carotenoid vibrations on both electronic ground and excited states as part of the system's Hamiltonian, reproduces all measured quantities. Importantly, the vibronic model presented here can explain the fast energy transfer rates with only moderate coupling constants, which are in agreement with structure based calculations. Counterintuitively, the vibrational levels on the carotenoid electronic ground state play the central role in the excited state population transfer to bacteriochlorophyll; resonance between the donor-acceptor energy gap and the vibrational ground state energies is the physical basis of the ultrafast energy transfer rates in these systems.

  6. Vibronic coupling explains the ultrafast carotenoid-to-bacteriochlorophyll energy transfer in natural and artificial light harvesters

    Energy Technology Data Exchange (ETDEWEB)

    Perlík, Václav; Seibt, Joachim; Šanda, František; Mančal, Tomáš [Institute of Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, Prague 121 16 (Czech Republic); Cranston, Laura J.; Cogdell, Richard J. [Institute of Molecular Cell and System Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow Biomedical Research Centre, 120 University Place, Glasgow G12 8TA, Scotland (United Kingdom); Lincoln, Craig N.; Hauer, Jürgen, E-mail: juergen.hauer@tuwien.ac.at [Photonics Institute, Vienna University of Technology, Gusshausstrasse 27, 1040 Vienna (Austria); Savolainen, Janne [Department of Physical Chemistry II, Ruhr-University Bochum, 44780 Bochum (Germany)

    2015-06-07

    The initial energy transfer steps in photosynthesis occur on ultrafast timescales. We analyze the carotenoid to bacteriochlorophyll energy transfer in LH2 Marichromatium purpuratum as well as in an artificial light-harvesting dyad system by using transient grating and two-dimensional electronic spectroscopy with 10 fs time resolution. We find that Förster-type models reproduce the experimentally observed 60 fs transfer times, but overestimate coupling constants, which lead to a disagreement with both linear absorption and electronic 2D-spectra. We show that a vibronic model, which treats carotenoid vibrations on both electronic ground and excited states as part of the system’s Hamiltonian, reproduces all measured quantities. Importantly, the vibronic model presented here can explain the fast energy transfer rates with only moderate coupling constants, which are in agreement with structure based calculations. Counterintuitively, the vibrational levels on the carotenoid electronic ground state play the central role in the excited state population transfer to bacteriochlorophyll; resonance between the donor-acceptor energy gap and the vibrational ground state energies is the physical basis of the ultrafast energy transfer rates in these systems.

  7. 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.

  8. Experimental Optimization of Direct-Drive Implosions with Cross-Beam Energy Transfer

    Science.gov (United States)

    Froula, D. H.; Igumenshchev, I. V.; Seka, W.; Edgell, D. H.; Goncharov, V. N.

    2011-10-01

    Cross-beam energy transfer (CBET) in direct-drive implosions is measured to reduce the hydrodynamic efficiency of the laser drive. The outer rays of each beam interact through the ion-acoustic waves to extract energy from the central rays of each beam. This accounts for an ~10% loss of absorption, which results in an ~20% reduction in hydro-efficiency as measured by the scattered light and x-ray bang time. Experiments that reduce the laser energy in the outer rays by reducing the ratio of the laser spot size to target diameter by Rbeam/Rtarget = 60% are shown to eliminate CBET and significantly increase the hydrodynamic coupling; however, the reduction in laser spot size leads to irradiation nonuniformities. An optimum laser spot size is experimentally determined that maximizes neutron yield by balancing the reduced CBET with the illumination nonuniformities. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302.

  9. Energy transfer pathways in the minor antenna complex CP29 of photosystem II : A femtosecond study of carotenoid to chlorophyll transfer on mutant and WT complexes

    NARCIS (Netherlands)

    Croce, Roberta; Müller, Marc G.; Caffarri, Stefano; Bassi, Roberto; Holzwarth, Alfred R.

    2003-01-01

    The energy transfer processes between carotenoids and Chls have been studied by femtosecond transient absorption in the CP29-WT complex, which contains only two carotenoids per polypeptide located in the L1 and L2 sites, and in the CP29-E166V mutant in which only the L1 site is occupied. The

  10. Effect of surface free energy on PDMS transfer in microcontact printing and its application to ToF-SIMS to probe surface energies.

    Science.gov (United States)

    Yang, Li; Shirahata, Naoto; Saini, Gaurav; Zhang, Feng; Pei, Lei; Asplund, Matthew C; Kurth, Dirk G; Ariga, Katsuhiko; Sautter, Ken; Nakanishi, Takashi; Smentkowski, Vincent; Linford, Matthew R

    2009-05-19

    Although polydimethylsiloxane (PDMS) transfer during microcontact printing (microCP) has been observed in previous reports, which generally focused on only one or a few different substrates, in this work we investigate the extent of PDMS transfer onto a series of surfaces with a wide range of hydrophobicities using an uninked, unpatterned PDMS stamp. These surfaces include clean silicon, clean titanium, clean gold, "dirty" silicon, polystyrene, Teflon, surfaces modified with PEG, amino, dodecyl, and hexadecyl monolayers, and also two loose molecular materials. The PDMS transferred onto planar surfaces is, in general, easily detected by wetting and spectroscopic ellipsometry. More importantly, it is detected by time-of-flight secondary ion mass spectrometry (ToF-SIMS) because of the sensitivity of this technique to PDMS. The effect of surface free energy on PDMS transfer in microcontact printing is investigated, and the relationship between the amount of PDMS in ToF-SIMS spectra and the surface tensions of initial surfaces is revealed. We show that PDMS transfer can be applied as a probe of surface free energies using ToF-SIMS, where PDMS preferentially transfers onto more hydrophilic surface features during stamping, with little being transferred onto very hydrophobic surface features. Multivariate curve resolution (MCR) analysis of the ToF-SIMS image data further confirms and clarifies these results. Our data lend themselves to the hypothesis that it is the free energy of the surface that plays a major role in determining the degree of PDMS transfer during microCP.

  11. Rapid energy modeling for existing buildings: Testing the business and environmental potential through an experiment at Autodesk

    Energy Technology Data Exchange (ETDEWEB)

    Deodhar, Aniruddha; Stewart, Emma; Young, Rahul; Khan, Haider

    2010-09-15

    Retrofits of existing buildings represent a huge, growing market and an opportunity to achieve some of the most sizable and cost-effective carbon reductions in any sector of the economy. More 'zero energy' and 'carbon neutral' buildings are being conceived daily by combining energy efficiency measures with renewable energy technologies. However, for all the progress, the building industry faces technical and cost challenges in identifying the highest potential retrofit candidates. This presentation investigates one potential solution, a technology driven workflow called rapid energy modeling, to accelerate and scale the process of analyzing performance for existing buildings in prioritizing improvements.

  12. A path to practical Solar Pumped Lasers via Radiative Energy Transfer.

    Science.gov (United States)

    Reusswig, Philip D; Nechayev, Sergey; Scherer, Jennifer M; Hwang, Gyu Weon; Bawendi, Moungi G; Baldo, Marc A; Rotschild, Carmel

    2015-10-05

    The optical conversion of incoherent solar radiation into a bright, coherent laser beam enables the application of nonlinear optics to solar energy conversion and storage. Here, we present an architecture for solar pumped lasers that uses a luminescent solar concentrator to decouple the conventional trade-off between solar absorption efficiency and the mode volume of the optical gain material. We report a 750-μm-thick Nd(3+)-doped YAG planar waveguide sensitized by a luminescent CdSe/CdZnS (core/shell) colloidal nanocrystal, yielding a peak cascade energy transfer of 14%, a broad spectral response in the visible portion of the solar spectrum, and an equivalent quasi-CW solar lasing threshold of 23 W-cm(-2), or approximately 230 suns. The efficient coupling of incoherent, spectrally broad sunlight in small gain volumes should allow the generation of coherent laser light from intensities of less than 100 suns.

  13. Fragment transition density method to calculate electronic coupling for excitation energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Voityuk, Alexander A., E-mail: alexander.voityuk@icrea.cat [Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain and Institut de Química Computacional i Catàlisi (IQCC), Universitat de Girona 17071 Girona (Spain)

    2014-06-28

    A general approach, the Fragment Transition Density (FTD) scheme, is introduced to estimate electronic coupling for excitation energy transfer in a molecular system. Within this method, the excitation energies and transition densities of the system are used to derive the coupling matrix element. The scheme allows one to treat systems where exciton donor and acceptor are close together and their exchange interaction and orbital overlap are significant. The FTD method can be applied in combination with any quantum mechanical approach to treat excited states of general nature including single-, double-, and higher excitations. Using FTD approach, we derive excitonic couplings for several systems computed with the CIS, TD DFT and MS-CASPT2 methods. In particular, it is shown that the estimated coupling values in DNA π-stacks are strongly affected by the short-range electronic interaction of adjacent nucleobases.

  14. Experimental study of plasma energy transfer and material erosion under ELM-like heat loads

    Energy Technology Data Exchange (ETDEWEB)

    Garkusha, I.E., E-mail: garkusha@ipp.kharkov.u [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine); Makhlaj, V.A.; Chebotarev, V.V. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine); Landman, I. [Forschungszentrum Karlsruhe, IHM, 76021 Karlsruhe (Germany); Tereshin, V.I.; Aksenov, N.N.; Bandura, A.N. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine)

    2009-06-15

    Main features of plasma-surface interaction and energy transfer to tokamak plasma facing components are studied at different heat loads in ELM simulation experiments with the plasma gun QSPA Kh-50. Repetitive plasma exposures of tungsten, graphite and different combined W-C targets were performed at the pulse duration of 0.25 ms and the heat loads varied in the range 0.2-2.5 MJ/m{sup 2}. The onset of vapor shield in front of the surface was investigated. The evaporation is immediately followed by a saturation of surface heat load if further increasing the impact energy. The presence of graphite essentially decreases the heat flux to the nearby tungsten surface, which is due to the carbon vapor shield. Droplet splashing at the tungsten surface and formation of hot spots on the graphite surface are discussed.

  15. Experimental study of plasma energy transfer and material erosion under ELM-like heat loads

    Science.gov (United States)

    Garkusha, I. E.; Makhlaj, V. A.; Chebotarev, V. V.; Landman, I.; Tereshin, V. I.; Aksenov, N. N.; Bandura, A. N.

    2009-06-01

    Main features of plasma-surface interaction and energy transfer to tokamak plasma facing components are studied at different heat loads in ELM simulation experiments with the plasma gun QSPA Kh-50. Repetitive plasma exposures of tungsten, graphite and different combined W-C targets were performed at the pulse duration of 0.25 ms and the heat loads varied in the range 0.2-2.5 MJ/m 2. The onset of vapor shield in front of the surface was investigated. The evaporation is immediately followed by a saturation of surface heat load if further increasing the impact energy. The presence of graphite essentially decreases the heat flux to the nearby tungsten surface, which is due to the carbon vapor shield. Droplet splashing at the tungsten surface and formation of hot spots on the graphite surface are discussed.

  16. 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.

  17. Temperature-Responsive Luminescent Solar Concentrators: Tuning Energy Transfer in a Liquid Crystalline Matrix.

    Science.gov (United States)

    Sol, Jeroen A H P; Dehm, Volker; Hecht, Reinhard; Würthner, Frank; Schenning, Albertus P H J; Debije, Michael G

    2018-01-22

    Temperature-responsive luminescent solar concentrators (LSCs) have been fabricated in which the Förster resonance energy transfer (FRET) between a donor-acceptor pair in a liquid crystalline solvent can be tuned. At room temperatures, the perylene bisimide (PBI) acceptor is aggregated and FRET is inactive; while after heating to a temperature above the isotropic phase of the liquid crystal solvent, the acceptor PBI completely dissolves and FRET is activated. This unusual temperature control over FRET was used to design a color-tunable LSC. The device has been shown to be highly stable towards consecutive heating and cooling cycles, making it an appealing device for harvesting otherwise unused solar energy. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  18. Transfer of energy between a pair of molecules near a plasmonic core-shell nanoparticle: Tunability and sensing

    Energy Technology Data Exchange (ETDEWEB)

    Daneshfar, Nader, E-mail: ndaneshfar@gmail.com, E-mail: ndaneshfar@razi.ac.ir; Yavari, Asghar [Department of Physics, Razi University, Kermanshah (Iran, Islamic Republic of)

    2016-05-15

    Our model is applied to the calculation of interaction energy between a pair of dipolar molecules (point dipoles) in the vicinity of a nanoshell monomer with core-shell structure, based on the dipole quasi-electrostatic theory of classical electrodynamics and using the Drude and Maxwell-Garnett model. In other words, this work discusses the intermolecular energy transfer from a donor molecule to an acceptor molecule near a spherical nanoparticle that is important for practical applications like sensing. It is shown that the proximity of plasmonic nanoparticles can have a strong effect on the energy transfer between molecules. In addition to the influence of the size, composition, embedding medium, and the filling fraction of doped particles on the interaction energy, the contribution of the dipolar, quadrupolar, octupolar, hexadecapolar, triakontadipolar, and higher order multipole interactions is presented and analyzed. Briefly, we will show that it is possible to achieve enhanced energy transfer by manipulation of different parameters as mentioned above.

  19. 'Energy challenges multiply rapidly' and 'The Book of Numbers'

    Energy Technology Data Exchange (ETDEWEB)

    Forbes, A.; Cragg, C.

    2008-07-15

    In two articles attention is paid to statistical data on energy, focusing on the BP Statistical Review of World Energy. From the first article it appears that a number of worrying themes emerge from detailed energy data for 2007 published by BP and Cedigaz. With energy demand rising inexorably and supply struggling to keep up, prices are probably to remain high and volatile, We are not running short of hydrocarbons yet, but bringing reserves to market is becoming increasingly difficult. And carbon emissions continue to rise rapidly. The second article focuses on the annually published BP Statistical Review of World Energy. The Review has now been published for over 50 years and remains by far the most accessible source of global energy statistics available. Looking back to the earliest editions not only reveals the astonishing, almost exponential, increase in the world's energy demand, but also how the preoccupations of the oil industry have changed down the years.

  20. 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