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Literatura académica sobre el tema "Excitation energy measurement"

Autor: Grafiati

Publicado: 4 de junio de 2021

Última modificación: 1 de febrero de 2022

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Artículos de revistas sobre el tema "Excitation energy measurement"

Stamatellou, Antiopi-Malvina y Anestis I. Kalfas. "On the Efficiency of a Piezoelectric Energy Harvester under Combined Aeroelastic and Base Excitation". Micromachines 12, n.º 8 (14 de agosto de 2021): 962. http://dx.doi.org/10.3390/mi12080962.

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A flutter-type, nonlinear piezoelectric energy harvester was tested in various combinations of aerodynamic and harmonic base excitation to study its power output and efficiency. The commercial polyvinylidene fluoride film transducer LDT1-028K was used in 33 excitation mode. The aerodynamic excitation was created by a centrifugal fan and the base excitation by a cone speaker. The excitations were produced by varying independently the mean airflow velocity and the frequency of base vibration. A capacitive load was used to store the harvested energy. A line laser was employed along with long exposure photography and high-speed video, for the visualization of the piezo film’s mode shapes and the measurement of maximum tip deflection. The harvested power was mapped along with the maximum tip deflection of the piezo-film, and a process of optimally combining the two excitation sources for maximum power harvesting is demonstrated. The energy conversion efficiency is defined by means of electrical power output divided by the elastic strain energy rate of change during oscillations. The efficiency was mapped and correlated with resonance conditions and results from other studies. It was observed that the conversion efficiency is related to the phase difference between excitation and response and tends to decrease as the excitation frequency rises.

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Ni, Pinghe, Yong Xia, Siu-Seong Law y Songye Zhu. "Structural Damage Detection Using Auto/Cross-Correlation Functions Under Multiple Unknown Excitations". International Journal of Structural Stability and Dynamics 14, n.º 05 (junio de 2014): 1440006. http://dx.doi.org/10.1142/s0219455414400069.

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Traditional structural system identification and damage detection methods use vibration responses under single excitation. This paper presents an auto/cross-correlation function-based method using acceleration responses under multiple ambient white noise or impact excitations. The auto/cross-correlation functions are divided into two parts. One is associated with the structural parameters and the other with the energy of the excitation. These two parts are updated sequentially using a two-stage method. Numerical and experimental studies are conducted to demonstrate the accuracy and robustness of the proposed method. The effects of measurement noise and number of measurement points on the identification results are also studied.

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Lövestam, Göran, Mikael Hult, Andreas Fessler, Thierry Gamboni, Joël Gasparro, Wouter Geerts, Ricardo Jaime, Patric Lindahl, Stephan Oberstedt y Hamid Tagziria. "Measurement of neutron excitation functions using wide energy neutron beams". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 580, n.º 3 (octubre de 2007): 1400–1409. http://dx.doi.org/10.1016/j.nima.2007.06.090.

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SINGH, B. P., M. G. V. SANKARACHARYULU, M. A. ANSARI, R. PRASAD y H. D. BHARDWAJ. "MEASUREMENT AND ANALYSIS OF EXCITATION FUNCTIONS FOR ALPHA-INDUCED REACTIONS IN BISMUTH". International Journal of Modern Physics E 01, n.º 04 (diciembre de 1992): 823–31. http://dx.doi.org/10.1142/s0218301392000357.

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Excitation functions for 209 Bi (α, 3n), 209 Bi (α, 4n) and 209 Bi (α, 5n) reactions have been measured in the energy range threshold to ≈50 MeV using stacked foil technique. Excitation functions have also been theoretically calculated and as expected, inclusion of pre-equilibrium contribution based on exciton model calculations along with compound nucleus calculations using Hauser–Feshbach formalism reproduces well the measured excitation functions. Interesting trend in the ratio of pre-equilibrium to equilibrium component with projectile energy has been observed.

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Omagari, Shun y Martin Vacha. "Toward accurate measurement of the intrinsic quantum yield of lanthanide complexes with back energy transfer". Physical Chemistry Chemical Physics 22, n.º 6 (2020): 3683–90. http://dx.doi.org/10.1039/c9cp06294g.

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Nokhbatolfoghahai, A., HM Navazi, Y. Ghobaad y H. Haddadpour. "Experimental measurement of energy density of a vibrating beam". Journal of Vibration and Control 24, n.º 24 (16 de febrero de 2016): 5735–46. http://dx.doi.org/10.1177/1077546316629596.

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This paper presents a method for calculating vibrational energy density from experimental data in a uniform beam. The input excitation is a point random force that induces transverse vibration along the beam. Using finite difference method and four accelerometers, both translational and rotational terms of kinetic and potential energy densities are measured. Also, an energy finite element analysis based computer program is developed. The results of the measurements achieved by developed formulation are compared with those of energy finite element analysis results. It is found that there is a fair agreement between them at relatively lower frequencies. But, in high frequencies, the difference between analytical and experimental results increases which stems from occurrence of errors in calculation of potential energy density. Finally, a comparison between kinetic and potential terms of the energy density is done. It is concluded that an efficient and very simple measurement procedure can be used based on kinetic energy measurement only.

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Sipos, Dávid y Dániel Feszty. "Development of a Procedure for the Validation of Statistical Energy Analysis Simulations". Acta Technica Jaurinensis 12, n.º 4 (27 de noviembre de 2019): 335–46. http://dx.doi.org/10.14513/actatechjaur.v12.n4.512.

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This paper describes the development of an NVH measurement procedure that can be used for comparisons to Statistical Energy Analysis (SEA). In SEA, the outputs of the simulation are ensemble averaged quantities for each subsystem, which can be obtained in measurements by averaging some measurement point results. For several reasons, the number of measurement points must be as few as possible, but at the same time, they have to provide a well approximated averaged response of the system. The sufficient number of evaluation points and excitation load cases are determined via Finite Element (FE) simulations. It is shown that in case of a simple, flat plate, 17 randomly chosen evaluation points in at least 3 load cases are enough to properly approximate the SEA results.

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Chen, Shuming, Dengfeng Wang y Yingfeng Lei. "Automotive Interior Noise Prediction Based on Single Sound Cavity Using Statistical Energy Analysis Method". Noise & Vibration Worldwide 42, n.º 11 (diciembre de 2011): 36–43. http://dx.doi.org/10.1260/0957-4565.42.11.36.

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In order to predict car interior noises at the car design and development stage, the statistical energy analysis (SEA) method was used. All the input parameters – modal density (MD), damping loss factor (DLF) and coupling loss factor (CLF) were calculated with SEA principle. Meanwhile, the sound excitation was calculated with sound power experiment data of internal combustion engine given by the engine manufacturer and sound source radiation formula. Engine mount excitation was also computed through the acceleration at initiative side of the engine mount and the transmissibility. A car virtual prototype was built to calculate a car body suspension receiving excitation from road roughness. A computational fluid dynamics (CFD) model was also built up to analyze the wind excitation on the outside surfaces. The car interior noises were predicted by the SEA model with all of the parameters and excitations. A good agreement was indicated by comparing predicted results with measured ones. The maximum relative error between prediction and measurement results is less than 3%, and the maximum absolute error is less than 2.5 dB (A). The above predicted results satisfy engineering precision requirements and as well as showing that using SEA method to predict car internal noises is feasible. The acoustic sensitivity analysis was made at the end. The car internal noise prediction method presented in the paper can be used at car design and development stage.

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Gragston, Mark, Paul Hsu, Anil Patnaik, Zhili Zhang y Sukesh Roy. "Time-Gated Single-Shot Picosecond Laser-Induced Breakdown Spectroscopy (ps-LIBS) for Equivalence-Ratio Measurements". Applied Spectroscopy 74, n.º 3 (10 de febrero de 2020): 340–46. http://dx.doi.org/10.1177/0003702819885647.

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Time-gated picosecond laser-induced breakdown spectroscopy (ps-LIBS) for the determination of local equivalence ratios in atmospheric-pressure adiabatic methane–air flames is demonstrated. Traditional LIBS for equivalence-ratio measurements employ nanosecond (ns)-laser pulses, which generate excessive amounts of continuum, reducing measurement accuracy and precision. Shorter pulse durations reduce the continuum emission by limiting avalanche ionization. Furthermore, by contrast the use of femtosecond lasers, plasma emission using picosecond-laser excitation has a high signal-to-noise ratio (S/N), allowing single-shot measurements suitable for equivalence-ratio determination in turbulent reacting flows. We carried out an analysis of the dependence of the plasma emission ratio Hα (656 nm)/NII (568 nm) on laser energy and time-delay for optimization of S/N and minimization of measurement uncertainties in the equivalence ratios. Our finding shows that higher laser energy and shorter time delay reduces measurement uncertainty while maintaining high S/N. In addition to atmospheric-pressure flame studies, we also examine the stability of the ps-LIBS signal in a high-pressure nitrogen cell. The results indicate that the plasma emission and spatial position could be stable, shot-to-shot, at elevated pressure (up to 40 bar) using a lower excitation energy. Our work shows the potential of using ps-duration pulses to improve LIBS-based equivalence-ratio measurements, both in atmospheric and high-pressure combustion environments.

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Eck, T., S. J. Walsh y J. L. Horner. "Measurement of Vibrational Energy and Point Mobility of a Beam Subjected to Moment Excitation Using a Finite-Difference Approximation". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 220, n.º 6 (1 de junio de 2006): 795–806. http://dx.doi.org/10.1243/09544062jmes210.

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Moment excitation is often neglected in structural vibration analysis because of difficulties in measuring the applied moment and the resulting wave motion in the structure. Further, it is often assumed that moment-induced vibrational energy is significant only in the high frequency region. However, recent studies have shown that moment excitation should be included in vibrational analysis at all frequencies, when the source location is in close proximity to a structural discontinuity. In this article, a novel method is presented to measure the point mobility and resulting vibrational energy of a beam subjected to moment excitation. The proposed method utilizes a finite-difference approximation to calculate the rotational motion of the beam at the point of excitation. Moment excitation is induced by a specially designed impact rig which applies two equal and opposite forces on two moment arms that are perpendicularly attached to the beam. It is shown that, using the newly developed technique, the measured point mobility follows the trend of the equivalent theoretical structure. The technique also showed good agreement over a wide frequency range between the measured input energy and the measured transmitted flexural wave energy along the beam.

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Tesis sobre el tema "Excitation energy measurement"

Burrows, Simon Adam. "Towards a precise measurement of the He'+ 2S lamb shift". Thesis, University of Sussex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390916.

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Li, Bin. "Experimental study on the fragmentation of adenine and porphyrin molecules induced by low energy multicharged ion impact". Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00807375.

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In this work, the Collision Induced Dissociation under Energy Control method was extended to study the fragmentation of gas-phase biomolecules adenine (H5C5N5) and porphyrin FeTPPCl (C44H28N4FeCl). The population distribution for each dissociation channel has been experimentally determined as a function of the excitation energy of the parent molecular ions at a well-determined initial charge state. In collisions between Cl+ and adenine (Ade) at 3keV, the fragmentation pattern of Ade2+ is dominated by the loss of H2CN+ and the successive emission of HCN. The energy distribution of the parent dications confirms the successive emission dynamics. A specific decay channel is observed, i.e., the emission of a charged H2CN+ followed by the emission of HC2N2. In Kr8+-FeTPPCl collisions at 80keV, parent ions FeTPPCl1+,2+,3+ are observed, along with the corresponding decay patterns. It is found that in the first step the dominant low-energy-cost decay channel is the emission of Cl0 independent of the initial charge state of FeTPPClr+ (r=1-3). For the resulted dication FeTPP2+, the dominant fragmentation channel is the neutral evaporation; for the trication however, the dominant fragmentation channel is the asymmetrical fission. In the case of H+ and F+ impact at 3keV, due to the different reaction windows opened in the two collision systems, different fragmentation patterns are observed. Furthermore, nH2 loss processes are observed. Additionally, the production yield of the negative ion emerged in F2+-Ade collision at 30keV is measured to be about 1% using a new experimental approach.

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Beyer, Andrew David Ooguri Hirosi Ooguri Hirosi. "Studies of the low-energy quasiparticle excitations in high-temperature superconducting cuprates with scanning tunneling spectroscopy and magnetization measurements /". Diss., Pasadena, Calif. : California Institute of Technology, 2009. http://resolver.caltech.edu/CaltechETD:etd-05272008-225257.

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CHANG, YU y 張郁. "Non-Markovianity Measurement and Coherent Modified RedfieldTheory in Simulating Dynamics of Excitation Energy Transfer". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/13071134660263428879.

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碩士
國立臺灣大學
化學研究所
103
Excitation energy transfer (EET) is a crucial process in many natural and artificial light-harvesting systems. Such process may occur when the energies of two weakly coupled electronic excitations are matched, which is widely recognized as a Förster resonance energy transfer. However, EET can also occur through a relaxation process especially for the cases, where the interaction between the interested system and its external environment is weak. This process is called a Redfield energy transfer. A successful theoretical method to simulate EET dynamics strongly depends on how to solve the balance between the two limits. In this study, we first investigate the shortcoming of the Markovian Redfield theory, which is widely used in simulating energy relaxation in molecular systems. We show that for general initial conditions, Markovian Redfield theory almost always yields dynamics that violates the positivity requirement for density matrices particularly on strong electron-phonon coupling and high temperature, making the theory inadequate for simulating EET in molecular systems. It is evident that the non-Markovian effects cannot be ignored in most situations. We then adopt the positivity violation to establish a non-Markovianity measure to quantify non-Markovian effects. To remedy the Redfield approach, a coherent modified Redfield theory was recently developed. Compared to traditional Förster and Redfield theory, the CMRT has a wider range of applicability resulting from the smaller perturbation and inclusion of multiphonon relaxation. In addition, by using a secular approximation to retain the major pathways in dissipation process, the secular CMRT can not only reduce the computational cost, but also capture the important coherent dynamics. In this work, the accuracy of CMRT is comprehensively investigated in the comparisons with numerically exact path-integral method. The results reveal an important role of “dynamical localization” when the coherence effect is overestimated. Finally, we apply the CMRT to study non-Förster EET dynamics in a silylene-spaced copolymer system. We reproduce the absorption and fluorescence spectra of the systems and derive parameters from spectral fitting. The parameters are subsequently used to calculate the EET dynamics, which allows us to describe both Förster and non-Förster dynamics in the system. We also investigated the effects of static energetic disorder on EET dynamics, which shows several dynamical groups with different EET rates. The energetic disorder causes a distribution of delocalization lengths, where the longer delocalization lengths characterized by strongly coherent systems is accounted for the fast dynamics. In summary, we examine the applicability of Markovian Redfield theory and simulate the EET dynamics with newly developed CMRT.

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Jen, Tzu-Hao y 任慈浩. "Investigation of Excitation Energy in Polymer Light-Emitting Diode: Measurement of Singlet to Triplet Ratio in Polymer Light-Emitting Diode and Effective Reduction of Quenching of Phosphor Triplet Exciton in Electrophosphorescent Polymer Light-Emitting Di". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/57903381361391647709.

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博士
國立清華大學
化學工程學系
97
Electroluminescence (EL) from organic molecules and conjugated polymers has attracted wide interest because of the large potential for application in display fabrication. In organic light-emitting diode (OLED),holes and electrons injected from the anode and cathode can recombine to yield singlet fraction (χS) of 25% according to quantum statistics and some experiments. However, for polymer light-emitting diodes (PLED), this fraction still remains under debate. Therefore, it is extremely important for us to clarify χS in the PLED and investigate its relation with molecular structure of conjugated polymer so that high χS conjugated polymers can be designed accordingly. In the first part of this thesis, a method is proposed to measure χS based on the measurement of phosphorescence decay of phosphorescent dopant in the polymer under electrical field excitation in the working device. We find that the χS in the blue emitting PCBPF based PLED exceeds the quantum statistics limit (25%) and increases with electric field excitation. It is probably resulted from triplet-triplet annihilation by a collision between two triplet excitons in the same chain to yield a singlet exciton. For purely fluorescent device, only singlet exciton is emissive and most energy is wasted by non-emissive triplet exciton. By doping with phosphor as guests in small molecules or polymers as hosts, both singlet and triplet exciton formed under electric field excitation can be harvested by the phosphor and consequently the internal quantum efficiency is possible to be promoted toward 100%. However, in order to confine triplet exciton on phosphor guest, a host material with triplet energy level (ET) higher than the phosphor guest is intuitively required as a significant quenching of triplet exciton by a low ET host for a high ET guests can occur。 In the second part of thesis, we demonstrate that an effective reduction of quenching of triplet exciton for a high ET phosphor guest with a low ET polymer host is possible upon introducing dense side chains to the polymer to block a direct contact from the guest such that possibility of Dexter energy transfer between them is reduced to a minimum. The system investigated is CzPPP (ET = 2.39 eV) as host and Ir-G (ET=2.41 eV) as guest, which gives high device efficiency (30 cd/A) and is more efficient than that (23 cd/A) in the system with high host triplet energy (PCBP, ET = 2.53 eV). This observation suggests a new route for molecular design of electroluminescent polymers as host for phosphorescent dopant：The ET of polymer host is not necessary to be higher than that of phosphor guest for efficient electrophosphorescence. Such finding provides a more freedom for molecular design of low ET electroluminescent polymers as host for high ET phosphor dopant.

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Toews, William Henry. "An investigation of low energy quasiparticle excitations via thermal conductivity measurements". Thesis, 2012. http://hdl.handle.net/10012/7122.

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Thermal conductivity measurements are made on a variety of systems in order to probe low energy quasiparticle excitations. In particular, thermal conductivity measurements were made on the iron based superconducting material LaFePO at temperatures from 60 mK to 1 K and in fields from 0 T to 5 T in order to shed light on the symmetry of the superconducting order parameter. A substantial non-zero electronic contribution to the thermal conductivity is observed and interpreted as sub-gap electronic quasiparticles which is clear evidence for a nodal gap symmetry. A high scattering rate and non-T3 temperature dependence of the conductivity is evidence against the d-wave scenario. However, the field dependence does seem to suggest that the anisotropic s+- picture is a likely candidate for the order parameter, although more theoretical work is required to confirm this. Thermal conductivity measurements were also made on the spin-ice system Ho2Ti2O7 between 50 mK and 1.4 K in applied magnetic fields from 0 T to 8 T in an attempt to observe the much debated magnetic monopole-like quasiparticles. An applied magnetic field of 8 T was applied along to [111] direction as to fully polarize the magnetic moments in order to extract the phonon contribution of the thermal conductivity. The low field thermal conductivity reveals evidence for an additional heat transfer mechanism that also scatters phonons which is magnetic in nature. This is taken to be evidence for the existence of monopole-like excitations out of the spin-ice ground state and is described by existing Debye-Huckel theory. Thermal transport was used in conjunction with charge conductivity to study the unconventional quantum critical point (QCP) in the heavy-Fermion superconductor beta-YbAlB4 at temperatures down to 60 mK and in fields up to 2 T. The results show that the Wiedemann-Franz law (WFL) is obeyed down to the lowest measured temperatures indicating that the Landau quasiparticles remain intact near the QCP. A small suppression of the Wiedemann-Franz ratio (L/L0 = kappa / sigma T L0) is seen at finite temperatures (T < 1 K) with minimal dependence on magnetic field. Comparing with other similar quantum critical systems, it becomes apparent that inelastic scattering events have little effect on the transport and are mainly field independent in beta-YbAlB4. An overview of the design for a new thermal conductivity mount is also presented. The design hinges around the idea of building the experiment mount into a small copper box rather than on an open frame. Not only does this provide mechanical stability for safe transportation, it also reduces the noise caused by electromagnetic interference (EMI) in the sample thermometers by more than a factor of ten over the old wire frame design.

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Beyer, Andrew David. "Studies of the Low-Energy Quasiparticle Excitations in High-Temperature Superconducting Cuprates with Scanning Tunneling Spectroscopy and Magnetization Measurements". Thesis, 2009. https://thesis.library.caltech.edu/2523/2/Thesis_AB_full.pdf.

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This thesis details the investigation of the unconventional low-energy quasiparticle excitations in both hole-and electron-type cuprate superconductors through experimental studies and theoretical modeling. The experimental studies include spatially resolved scanning tunneling spectroscopy (STS) experiments and bulk magnetization measurements, and the theoretical modeling involves developing a phenomenology that incorporates coexisting competing orders and superconductivity in the ground state of the cuprates.

Magnetic field and temperature dependent evolution of the spatially resolved quasiparticle excitation spectra in the electron-type cuprate La_0.1Sr_0.9CuO₂ (La-112), the simplest structured cuprate superconductor with T_C = 43 K, are investigated experimentally for the first time. For temperature (T) less than the superconducting transition temperature (T_C), and in zero field, the quasiparticle spectra of La-112 exhibits gapped behavior with two coherence peaks and no satellite features. For magnetic field measurements at T << T_C, vortices are observed in La-112, which is the first direct observation of vortices among electron-type cuprate superconductors. Moreover, pseudogap-like spectra are revealed inside the core of vortices, where superconductivity is suppressed. The intra-vortex pseudogap-like spectra are characterized by an energy gap of V_PG=(8.5±0.6)meV, while the inter-vortex quasiparticle spectra show larger peak-to-peak gap values characterized by Δ_pk-pk(H) ≥ V_PG, and Δ_pk-pk(0)=(12.2±0.8)meV ≥Δ_pk-pk(H>0). The quasiparticle spectra are found to be gapped at all locations up to the highest magnetic field examined (H = 6T) and reveal an apparent low-energy cutoff at the V_PG energy scale. This finding is in stark contrast to the vortex-state quasiparticle spectra in conventional superconductors, where the intra-vortex spectra near vortex cores exhibit a sharp zero-bias conductance peak due to the complete suppression of superconductivity and the presence of continuous bound quasiparticle states. The lack of a zero-bias peak and the observation of pseudogap-like spectra in the intra-vortex quasiparticle spectra of La-112 suggest that superconductivity alone cannot describe the STS results.

Similar studies of the magnetic field and temperature dependent evolution of the spatially resolved quasiparticle excitation spectra in the hole-type cuprate YBa₂Cu₃O_7-δ (Y-123) have also been carried out. The quasiparticle spectra for T << T_C(~93 K) show satellite features at an energy higher than the superconducting gap, and the superconducting gap is found to be associated with a set of coherence peaks for H = 0. The coherence peaks are homogeneous, with a energy gap given by Δ_SC=(20±1)meV, and may be attributed to superconductivity. The satellite features are less homogeneous, with a effective gap energy Δ_eff=(37.8±2.0)meV. The application of magnetic fields reveal vortices in Y-123, and the intra-vortex quasiparticle spectra show two energy gaps, with one gap at the pseudogap energy scale V_PG~32meV and the other gap at the subgap energy scale Δ' ~ 7-12meV < Δ_SC. In contrast, the inter-vortex quasiparticle spectra reveal only one energy gap at Δ_SC~20meV. A dramatic shift in the peak-to-peak gaps, Δ_pk-pk(H), from Δ_SC to both V_PG and Δ' with increasing magnetic field is observed. In addition, higher spatial resolution STS measurements were performed in Y-123 to investigate the spatial dependence of the quasiparticle spectra in more detail. The experimental resolution allowed Fourier-transformed local density of states analysis to be performed. Energy-dependent dispersive diffraction modes attributable to quasiparticle scattering interferences (QPI) were seen, as well as three energy-independent modes not due to QPI. The energy-independent modes corresponded to periodic real-space conductance modulations along the Cu-O bonding and the nodal directions attributable to a pair-density wave, a charge-density wave, and a spin-density wave. The totality of data in Y-123 suggests that the ground state of Y-123 contains competing orders coexisting with superconductivity and not superconductivity alone.

In addition to the STS experiments, the effects of unconventional quasiparticle excitations on macroscopic superconductivity and vortex phase diagrams are investigated from bulk magnetization measurements on several different families of superconducting cuprate samples. Evidence for strong field-induced quantum phase fluctuations and quantum criticality are observed in the vortex phase diagrams of all samples considered. The origin of the apparent quantum criticality and strong field-induced quantum phase fluctuations due to the nearby presence of competing orders is discussed.

Finally, a "two-gap" phenomenological model, describing the excitations from a ground state of coexisting superconductivity and a competing order, is used to quantitatively model the unconventional quasiparticle excitations observed in the measurements of the local tunneling density of states and the angle-resolved photoemission spectroscopy (ARPES) experiments. The phenomenological model is found to provide consistent accounts for the quasiparticle tunneling data from our measurements in La-112 and Y-123, as well as experimental data by others on different cuprates.

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Libros sobre el tema "Excitation energy measurement"

Course on Advances and Methods in the Study of Atomic Doubly Excited States (1995 Medellin, Colombia). Proceedings of the Course on Advances and Methods in the Study of Atomic Doubly Excited States: [Medellín, Colombia, April 24-29, 1995]. Editado por Mahecha Jorge y Botero Javier. Medellín, Colombia: Universidad de Antioquia, Departamento de Física, 1995.

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Tiwari, Sandip. Electromechanics and its devices. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198759874.003.0005.

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Electromechanics—coupling of mechanical forces with others—exhibits a continuum-to-discrete spectrum of properties. In this chapter, classical and newer analysis techniques are developed for devices ranging from inertial sensors to scanning probes to quantify limits and sensitivities. Mechanical response, energy storage, transduction and dynamic characteristics of various devices are analyzed. The Lagrangian approach is developed for multidomain analysis and to bring out nonlinearity. The approach is extended to nanoscale fluidic systems where nonlinearities, fluctuation effects and the classical-quantum boundary is quite central. This leads to the study of measurement limits using power spectrum and, correlations with slow and fast forces. After a diversion to acoustic waves and piezoelectric phenomena, nonlinearities are explored in depth: homogeneous and forced conditions of excitation, chaos, bifurcations and other consequences, Melnikov analysis and the classic phase portaiture. The chapter ends with comments on multiphysics such as of nanotube-based systems and electromechanobiological biomotor systems.

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Solymar, L., D. Walsh y R. R. A. Syms. Semiconductors. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198829942.003.0008.

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Both intrinsic and extrinsic semiconductors are discussed in terms of their band structure. The acceptor and donor energy levels are introduced. Scattering is discussed, from which the conductivity of semiconductors is derived. Some mathematical relations between electron and hole densities are derived. The mobilities of III–V and II–VI compounds and their dependence on impurity concentrations are discussed. Band structures of real and idealized semiconductors are contrasted. Measurements of semiconductor properties are reviewed. Various possibilities for optical excitation of electrons are discussed. The technology of crystal growth and purification are reviewed, in particular, molecular beam epitaxy and metal-organic chemical vapour deposition.

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Chen-hua, Chang, McCollom Alex D y United States. National Aeronautics and Space Administration., eds. On the uncertainty in single molecule fluorescent lifetime and energy emission measurements: Technical report 94-03. [Washington, D.C.]: National Aeronautics and Space Administration, 1994.

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Capítulos de libros sobre el tema "Excitation energy measurement"

Grinberg, Marek. "Principles of Energetic Structure and Excitation-Energy Transfer Based on High-Pressure Measurements". En Phosphors, Up Conversion Nano Particles, Quantum Dots and Their Applications, 67–151. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-52771-9_4.

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Politano, Antonio y Gennaro Chiarello. "Probing Collective Excitations in Graphene/Metal Interfaces by High-Resolution Electron Energy Loss Spectroscopy Measurements". En Graphene Science Handbook, 573–88. Boca Raton, FL : CRC Press, Taylor & Francis Group, 2016. | “2016: CRC Press, 2016. http://dx.doi.org/10.1201/b19642-35.

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Müller-Dethlefs, Klaus y Edward W. Schlag. "Bond-Selective Memory Effects for 1s-Level Excitation of Molecules: Zero Kinetic Energy (Zeke) Electron-Photoion Coincidence Measurements". En The Jerusalem Symposia on Quantum Chemistry and Biochemistry, 371–92. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-2642-7_26.

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"Experimental Measurement of Excitation Transfer". En Energy Transfer in Macromolecules, editado por Nikolai Vekshin. SPIE, 1996. http://dx.doi.org/10.1117/3.pm26.ch4.

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Shapiro, Howard M. "Fluorescent Probes". En Flow Cytometry for Biotechnology. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780195183146.003.0006.

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In the jargon of cytometry, cellular characteristics, such as size, nucleic acid content, and membrane potential, are usually referred to as parameters, a term that is also used for the physical characteristics, such as absorption, light scattering, and fluorescence intensity, that are measured by cytometric instrumentation. Fluorescence, as a physical parameter, plays a key role in the detection of probes on beads for multiplexed analysis. Cellular parameters can be classed as intrinsic or extrinsic. Intrinsic cellular parameters are those that can be measured without the use of a reagent; measurement of extrinsic parameters requires the use of reagents, which are almost always referred to as probes, thereby occasioning confusion among molecular biologists new to cytometry. Cellular parameters are also characterized as structural or functional; DNA and RNA content and the presence and copy number of an antigen or nucleic acid sequence are structural parameters, whereas internal pH, membrane potential, and enzyme activity are functional parameters. The distinction between structural and functional parameters blurs at the edge, but the concept has been generally useful. Fluorescent probes allow measurement of the widest variety of extrinsic cellular parameters. For an atom or molecule to fluoresce, it must first absorb a photon, raising an electron to a higher energy level that is known as an excited state. Excitation by absorption requires only about a femtosecond. Fluorescence occurs when the electron loses all or some of the absorbed energy by emission of a photon. The fluorescence lifetime, that is, the period between excitation and emission, is typically on the order of a few nanoseconds for fluorescent organic materials but is notably longer (hundreds of microseconds) for some materials (e.g., lanthanide chelates). In almost all cases, some of the excitation energy is lost nonradiatively by transitions between different vibrational energy levels of the electronic excited state; this loss requires that the emitted energy be less than the energy absorbed, meaning that the fluorescence emission will be at a longer wavelength than the excitation. The difference between the principal excitation and emission maxima in the fluorescence spectrum is known as the Stokes shift, honoring George Stokes, who first described fluorescence in the mid-1800s. Typical Stokes shifts are no more than a few tens of nanometers.

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Magee, Patrick y Mark Tooley. "Electrophysiology and Stimulation". En The Physics, Clinical Measurement and Equipment of Anaesthetic Practice for the FRCA. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199595150.003.0022.

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This chapter covers the processing and application of electrical signals from the body, in particularly the electroencephalogram (EEG), the electrocardiogram (ECG), and the electromyogram (EMG). The EEG and ECG will be considered in their monitoring capacity. The EMG will be discussed along with simulation and neuromuscular blockade and monitoring. The electrocardiogram (ECG) is a surface reflection of the propagation of electrical depolarisation and repolarisation over the various contractile chambers of the heart. Depolarisation is the trigger for releasing the stored contractile energy in the cardiac muscle. Each chamber also produces electrical action and polarising recovery potentials associated with the mechanical contribution of the recovery. The ECG can be divided into two major components: one associated with the propagation of excitation and recovery of the atria; the other with these events occurring in the ventricles. Excitation of the atria gives rise to the P wave, after which the atrial contractions propel blood into the ventricles. An atrial recovery wave exists, but it is rarely seen, as it is obscured by ventricular excitation, which is signalled by the QRS wave. During the later part of the QRS wave, ventricular contraction commences. Recovery of the ventricles is preceded by the T wave. The ECG labels, i.e. PQRST, are shown in Figure 18.1. To localise the direction of excitation and recovery of the heart chambers (and also to estimate the extent of cardiac injury), a variety of electrode arrangements can be used. The electrodes (which are normally disposable silver–silver chloride as described in Chapter 5) are positioned on easily located anatomical landmarks such as the right arm (RA), the left arm (LA), and the left leg (LL), with the right leg usually providing the reference or common. The standard (1, II, III), augmented (aVR, aVL, aVF) and precordial (V) leads are routinely recorded by electrocardiographers. It is possible to locate the direction of excitation and recovery by considering that the direction of the event (excitation or recovery) is at right angles to the isoelectric lead (i.e. the lead with equal forces in the positive and negative). This can be demonstrated by forming an equilateral triangle (Einthoven’s triangle) such as in Figure 18.2(a).

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Drickamer, H. G. "Pressure-Tuning Spectroscopy: A Tool for Investigating Molecular Interactions". En High Pressure Effects in Molecular Biophysics and Enzymology. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195097221.003.0005.

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Pressure-tuning spectroscopy is a powerful tool for investigating molecular interactions. These interactions may involve organic or inorganic materials in liquid, polymeric, or crystalline media. In this article we confine our attention to organic molecules, largely in dilute solution in polymers or liquids. We demonstrate the use of high-pressure luminescence to study the effect of the environment on π* →π, π* →n and charge-transfer excitations, as well as the interaction between singlet and triplet states. In addition, we provide tests of the energy gap law for non-radiative dissipation of excitation, the role of viscosity in luminescent efficiency, and the internal consistency of various means of predicting and correlating energy transfer. Over the past 40 years, it has been amply demonstrated that high pressure is a powerful tool for studying electronic phenomena in condensed phases. The basic concept is as follows. The optical, electrical, magnetic, and chemical properties—collectively the electronic properties—of condensed phases depend on the interactions of the outer electrons on the atoms, molecules, or ions that make up the phase. Different kinds of electronic orbitals have different spatial characteristics—different radial extent, different shape (orbital angular momentum), and different diffuseness; therefore, pressure perturbs the energies associated with these orbitals in different degrees. This relative perturbation we call “pressure tuning,” and the measurement and explanation of the tuning is “pressure-tuning spectroscopy.” Pressure-tuning spectroscopy of the vibrational and rotational excitations of atoms in molecular and in crystal lattices is also an active and important field, but in this article we arc concerned mainly with electronic phenomena. We further limit this discussion primarily to organic molecules in solid polymers or liquid solutions, as these have the greatest relevance to biologically active systems. A variety of probes are used for studying electronic phenomena under high pressure, but the emphasis here is on luminescence. The presentation consists of a series of examples of various types of excitations on interactions where high pressure has been an effective tool. Only references directly relevant to each example are included. Two general references to pressure studies of molecular luminescence have been published (Drickamer, 1982, 1990).

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Bradrick, Thomas D. y Jorge E. Churchich. "Time-resolved fluorescence and phosphorescence spectroscopy". En Spectrophotometry and Spectrofluorimetry. Oxford University Press, 2000. http://dx.doi.org/10.1093/oso/9780199638130.003.0007.

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In this chapter, we outline the basic theory and methodology for making time resolved fluorescence and phosphorescence measurements. We begin with a brief discussion of the intrinsic time dependence of fluorescence and phosphorescence decays, and also introduce several important photophysical concepts. Energy transfer measurements, which are important for determining molecular distances, are then addressed, followed by the convolution integral (which describes the luminescence decay that is actually observed in pulsed excitation experiments) and the relationships that are used to determine fluorescence lifetimes from phase/modulation data. Polarized fluorescence measurements, which are an important tool for following molecular motions, are then discussed, and the fluorescence portion of the chapter concludes with an overview of data analysis and brief descriptions of the instrumentation that is used in making time-resolved fluorescence measurements. The remainder of the chapter is then devoted to a discussion of phosphorescence spectroscopy. The intrinsic time dependence of fluorescence decays is derived in Section 3.3 of Chapter 2. There it is shown that if a population of excited singlet-state molecules is generated instantaneously, its size decreases exponentially with time, as does the intensity of the emitted photons. The fluorescence lifetime τS is typically used to describe the rate of decay, where τs-1 = kR + kNR + kISC + kPR and kR, kNR, kISC and kpR are the rate constants for the various parallel unimolecular de-excitation processes. If there are several non-interacting fluorophore species in solution, their excited states will decay independently and a sum of exponentials will be needed to describe how the sample’s fluorescence intensity decreases with time.

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Kumar, Rohit, Qiucheng Yu, Domenico Paparo y Andrea Rubano. "TeraVision: A LabVIEW Software for THz Hyper-Raman Spectroscopy". En LabVIEW - A Flexible Environment for Modeling and Daily Laboratory Use. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96663.

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Terahertz Time-Domain Spectroscopy (TDS) has emerged during the last two decades as a very popular technique for characterizing the low-energy excitations of several materials, gaseous, liquids and solids, as well as artificial materials as for instance epitaxial heterostructures and more. In recent years, the advances in THz technology allowed obtaining nonlinear optical effects with THz photons, showing remarkable results. In particular, THz Hyper-Raman Spectroscopy greatly expands the spectroscopic capability of the standard THz-TDS by combining intense and broadband THz pulses with a detailed analysis of the spectral content of the generated signal. It is evident that this improvement needs an adequate software support. The main parameter for coding the software which differs with respect to a standard THz-TDS software is the control of a motorized grating (monochromator), but several routines employed in the setup optimization stage rather than the actual measurement are needed as well. In this paper we present the TeraVision software, based on LabVIEW code, in order to highlight the solutions we adopted to tackle the main experimental challenges as well as to give a pleasant and user-friendly experience to expert users.

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Actas de conferencias sobre el tema "Excitation energy measurement"

Ren, Zhang-ao, Zhiqiang He, Zhang Xuan, Yalin Yan, Zhuohong Pan y Xiaohui Hu. "Measurement of the Resistive Component of Grounding Impedance by Square Wave Excitation". En 2020 IEEE 4th Conference on Energy Internet and Energy System Integration (EI2). IEEE, 2020. http://dx.doi.org/10.1109/ei250167.2020.9346916.

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DeLuca, Nicholas J., Richard B. Miles, Waruna D. Kulatilaka, Naibo Jiang y James R. Gord. "Femtosecond Laser Electronic Excitation Tagging (FLEET) Fundamental Pulse Energy and Spectral Response". En 30th AIAA Aerodynamic Measurement Technology and Ground Testing Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2014. http://dx.doi.org/10.2514/6.2014-2227.

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Trigona, Carlo, Jaakko Palosaari y Yang Bai. "A vibrational energy harvester based on Soft-Nonlinearity for truly random excitation". En 2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC). IEEE, 2020. http://dx.doi.org/10.1109/i2mtc43012.2020.9128595.

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Li, Yongjian, Jianguo Zhu, Qingxin Yang, Zhi Wei Lin, Yi Wang y Wei Xu. "Magnetic properties measurement of soft magnetic composite materials over wide range of excitation frequency". En 2010 IEEE Energy Conversion Congress and Exposition (ECCE). IEEE, 2010. http://dx.doi.org/10.1109/ecce.2010.5617845.

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Maslov, N. A. y E. O. Tsibulskaya. "Investigation of the photobleaching effect on the measurement of laser-induced fluorescence excitation-emission matrices of biological tissues". En HIGH-ENERGY PROCESSES IN CONDENSED MATTER (HEPCM 2019): Proceedings of the XXVI Conference on High-Energy Processes in Condensed Matter, dedicated to the 150th anniversary of the birth of S.A. Chaplygin. AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5117387.

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Riedelmeier, Stefan, Stefan Becker y Eberhard Schlücker. "Influence of Excitation on Junction Coupling at Water Hammer in Piping Systems". En ASME 2014 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/pvp2014-28065.

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A comprehensive study on junction coupling in two piping system configurations in dependency of the excitation’s condition were performed. The source of the hydraulic excitation is characterized by water hammer produced at various initial mean flow velocities. The resulting forces on the piping system caused bend oscillations. For each system configuration and initial mean flow velocity the support position of the bend was varied. Thus the structural frequency was altered. The pressure inside the pipe, the displacement of the bend, the acceleration at the anchorage and the supports were recorded. Additionally, optical measurement equipment was utilized in order to characterize the structural oscillation more detailed. For both system configurations fluid-structure interaction effects were identified, but two-way effects at the base frequency of water hammer only occurred in one system. The amplitude of excitation had influence on the amplitudes of the pressure, displacement and acceleration and on the number of modes which built up. The results of the measurements pointed out that not only the bend oscillated but also the anchorage and pipe sections behind the bend. In both systems, an energy transfer from the fluid to the anchorage could be observed. Due to the bending of the anchorage, the bends oscillated in multiple directions.

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Wang, L. P. y Z. M. Zhang. "Measurement of Coherent Thermal Emission From Subwavelength Grating Structures by the Excitation of Magnetic Polaritons". En ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/mnhmt2012-75112.

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Tailoring radiative properties such as spectral control of thermal emission is beneficial in many applications such as space cooling and energy harvesting. The effect of magnetic polaritons (MPs) on spectral modulation has been analyzed previously and shown to exhibit omnidirectional behaviors when magnetic polaritons are excited in metallic grating structures with a dielectric spacer on a metallic film. The present work provides an experimental demonstration of coherent thermal emission from such a microstructure in the infrared region at both room and elevated temperatures. Samples with different patterns are fabricated to study the geometric effect on the MPs. The emittance at elevated temperatures is directly measured using a home-built emissometer, while the room-temperature emittance is indirectly obtained from the reflectance measurements. The rigorous coupled-wave analysis and the LC model are employed to elucidate the mechanisms, by incorporating the Drude model with a temperature-dependent scattering rate.

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Marinis, Ryan T. y Ryszard J. Pryputniewicz. "Direct Measurement of Gyroscope Quadrature Error Using Interferometric Tools". En ASME 2009 InterPACK Conference collocated with the ASME 2009 Summer Heat Transfer Conference and the ASME 2009 3rd International Conference on Energy Sustainability. ASMEDC, 2009. http://dx.doi.org/10.1115/interpack2009-89222.

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A tuning fork gyroscope (TFG) functions by sensing a Coriolis acceleration. Proof masses are excited in plane, such that the motion is sinusoidal. A rotation, normal to the excitation direction, results in a Coriolis acceleration based on the cross product of the input rotation and the proof mass in-plane velocity. The Coriolis force displaces the proof mass, normal to the chip by an amount related to input rotation. The in-plane (drive) and out-of-plane (sense) motions of the proof masses are offset by 90°, placing these positions in quadrature. Quadrature error is present when the proof masses do not oscillate in plane, but rather have a small degree of out-of-plane motion. This error may cause a zero rate output in the sensor, also known as a bias error. A methodology is presented for using interferometry to directly measure the quadrature motion. Optical interferometry uses non-contact methods for shape measurement, with high accuracy normal to the viewing plane. Measurements may be made on the proof masses, while running, by utilizing a strobe illumination source. By matching the strobe frequency with the gyroscope resonance the motion is frozen to the camera, during which time quantitative measurements are made. This process is repeated at various positions of the in-plane proof mass motion and analyzed to reveal the degree of out-of-plane displacements of the proof masses while running.

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Liu, Weibing, Shizhi Zhao, Lu Cheng, Song Ai y Xiaoping Fan. "Vibration Analysis and Measurement Investigation of Gas Turbine Combustor Liner". En ASME 2017 Power Conference Joint With ICOPE-17 collocated with the ASME 2017 11th International Conference on Energy Sustainability, the ASME 2017 15th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2017 Nuclear Forum. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/power-icope2017-3301.

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Acoustic coupling effect in the combustion of fuel is the root of causing the combustor liner vibration. When the excitation frequency and the combustor liner structure natural frequency coincides or nearly, the combustor liner will resonate even cause structural damage. In order to regulate natural frequencies of combustor liner structure to avoid the oscillation frequency effectively that under the working condition, combustor liner design must include appropriate research and experimental verification of its vibration characteristics. The effectiveness of the combustor liner vibration design method and the reliability of combustor liner safe operation are verification effectively by vibration analysis and measurement investigation of gas turbine combustor liner. Technical support and follow-up to ensure safe operation of the new combustor liner design can be provided.

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Tran, Michael y Trinh Pham. "Laser-Induced Incandescence and Smoke Point Measurements to Characterize the Sooting Propensity of Biodiesel Diffusion Flame". En ASME 2010 4th International Conference on Energy Sustainability. ASMEDC, 2010. http://dx.doi.org/10.1115/es2010-90202.

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Combustion of biodiesel is rapidly expanding around the world, mainly for its significant reduction of emissions such as soot particulates. The presence of carbonaceous soot emitted indicates a reduction in efficiency of practical combustion systems. In addition, sub-micron soot particles can have substantial impact on the environment and human health. Common emission studies of neat and blends of biodiesel and diesel fuels have been investigated using compression ignition engines and capturing soot particles in the post-combustion zone. However, soot particles produced in the primary combustion zone can greatly influence the products in the post-combustion zone. To study soot formation in the primary combustion zone, laser diagnostic is performed on a laminar diffusion wick lamp. In this paper, the sooting propensity of various blends of soybean biodiesel and Ultra Low Sulfur Diesel (ULSD) fuels are investigated using both a traditional ASTM D-1322 standard smoke lamp and modern Laser-Induced Incandescence (LII) technique. Laser excitation is achieved using a pulsed Nd: YAG laser operating at 532nm wavelength. Although ultraviolet and infrared spectra can be used, the choice of an Nd: YAG laser operating at the second harmonic wavelength is preferred because interference from excitation of polycyclic aromatic hydrocarbons (PAHs) and the C2 Swan band can be reduced. A fast-gate Intensified Charge Coupled Device (ICCD) camera and a 450nm narrow band-pass filter are used to detect the spatially resolved LII signal. The qualitative LII signal provides the soot profile of different volume mixtures of biodiesel and diesel diffusion flame. Many researches report show reduction in soot particles emitted in the exhaust when biodiesel is used as a blend in compression ignited engines. The contribution of this research is to investigate whether similar sooting characteristics can be seen in the primary combustion zone by making measurements in the proximity of the flame front. In general, the LII signals and smoke point measurements show a decrease in soot particles produced when blending ratios of 25% biodiesel – 75% diesel (by volume) are used. One limitation of using the ASTM standard wick lamp is flame instability at higher blending ratios due to the increases in carbon deposit on the wick, which reduces the fuel vaporization rate. Therefore, smoke point measurement for blending ratios above B25 is not accurate since the flame height is not stable; hence, future experiments rely on LII technique to characterize soot emission properties. In order to perform LII laser diagnostics using higher blending ratios, comparison between smoke point measurements and LII signals will be characterized in this report using lower blending ratios.

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Informes sobre el tema "Excitation energy measurement"

Howell, R. B., R. J. Fonck, R. J. Knize y K. P. Jaehnig. Corrections to charge exchange spectroscopic measurements in TFTR due to energy-dependent excitation rates. Office of Scientific and Technical Information (OSTI), agosto de 1988. http://dx.doi.org/10.2172/6838276.

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