Primary Excitation Research Articles

Familiarity with a Tool Influences Peripersonal Space and Primary Motor Cortex Excitability of Muscles Involved in Haptic Contact

Long-term experience with a tool stably enlarges peripersonal space (PPS). Also, gained experience with a tool modulates internal models of action. The aim of this work was to understand whether the familiarity with a tool influences both PPS and motor representation. Toward this goal, we tested in 13 expert fencers through a multisensory integration paradigm the embodiment in their PPS of a personal (pE) or a common (cE) épée. Then, we evaluated the primary motor cortex excitability of proximal (ECR) and distal (APB) muscles during a motor imagery (MI) task of an athletic gesture when athletes handled these tools. Results showed that pE enlarges subjects’ PPS, while cE does not. Moreover, during MI, handling tools increased cortical excitability of ECR muscle. Notably, APB’s cortical excitability during MI only increased with pE as a function of its embodiment in PPS. These findings indicate that the familiarity with a tool specifically enlarges PPS and modulates the cortical motor representation of those muscles involved in the haptic contact with it.

Vibration suppression of nonlinear rotating metamaterial beams

In this paper, we investigate the nonlinear vibration of a metamaterial structure that consists of a rotating cantilever beam attached to a periodic array of spring–mass–damper subsystems deployed for vibration suppression. The full nonlinear model of the system is developed. The nonlinear response due to a primary resonance excitation is investigated, and the capability of the metastructure to suppress vibration is examined. The mass of the resonators (absorbers) comes at the expense of the host structure’s mass itself, which makes the total mass of the system conservative. Free and forced vibration analyses are performed. We first use the method of multiple scales to analyze the nonlinear behavior of rotating beams. The perturbation solutions are validated against their numerical counterparts. Results show the presence of a critical rotational speed at which the beam undergoes bifurcation and starts to flutter. The addition of the absorbers is observed to slightly reduce this critical speed. Nevertheless, the amplitude of limit-cycle oscillations beyond bifurcation is found to decrease when equipping the rotating beam with local absorbers. The results demonstrate the capability of the metamaterial structure as an efficient damping treatment. Furthermore, we show that careful placement of the absorbers along the cantilever beam (close to the tip) enables further vibration mitigation.

Charge Separation from an Intra-Moiety Intermediate State in the High-Performance PM6:Y6 Organic Photovoltaic Blend.

Bulk-heterojunction organic photovoltaic devices with nonfullerene acceptors (NFAs) exhibit efficient hole transfer with small interfacial energy offset, which results in power conversion efficiencies above 17% in single junction devices using the high-performance NFA of Y6. However, the underlying mechanism responsible for the hole transfer channel in the polymer/Y6 blends remains poorly understood. Herein, we report that the hole transfer channel of photocharge generation is mediated by an intra-moiety excited state in a blend of donor polymer PM6 and NFA Y6 using broadband transient absorption (TA) spectroscopy. By comparing the TA data recorded from the solution and film Y6 samples, we identify the ultrafast formation of an intra-moiety excimer state together with the conversion from the primary local excitation on a time scale of ∼0.2 ps in the Y6 film. The intra-moiety excimer state acts as the intermediate for the hole transfer channel, which dissociates into free polarons on a time scale of ∼15 ps in the PM6/Y6 blend at room temperature. The intra-moiety intermediate state, arising from the intermolecular coupling in Y6 domains, is markedly different from the interfacial charge transfer state, which is commonly accepted as the intermediate state for the electron transfer channel. These findings suggest that manipulating the interplay between intra-moiety and interfacial excited species can provide a promising route for further improving device performance.

Low‐frequency dipolar electromagnetic scattering by a solid ellipsoid in lossless environment

AbstractElectromagnetic wave scattering phenomena for target identification are important in many applications related to fundamental science and engineering. Here, we present an analytical formulation for the calculation of the magnetic and electric fields that scatter off a highly conductive ellipsoidal body, located within an otherwise homogeneous and isotropic lossless medium. The primary excitation source assumes a time‐harmonic magnetic dipole, precisely fixed and arbitrarily orientated that operates at low frequencies and produces the incident fields. The scattering problem itself is modeled with respect to rigorous expansions of the electromagnetic fields at the low‐frequency regime in terms of positive integral powers of the real wave number of the ambient. Obviously, the Rayleigh static term and a few dynamic terms are sufficient for the purpose of the present work, as the additional terms are neglected due to their minor contribution. Therein, the classical Maxwell's theory is suitably modified, leading to intertwined either Laplace's or Poisson's equations, accompanied by the impenetrable boundary conditions for the total fields and the limiting behavior at infinity. On the other hand, the complete spatial anisotropy of the three‐dimensional space is secured via the introduction of the genuine ellipsoidal coordinate system, being appropriate for tackling incrementally such scattering boundary value problems. The nonaxisymmetric fields are obtained via infinite series expansions in terms of ellipsoidal harmonic eigenfunctions, providing handy closed‐form solutions in a compact fashion, whose validity is verified by a straightforward reduction to simpler geometries of the metal object. The main idea is to demonstrate an efficient methodology, according to which the constructed analytical formulae can offer the appropriate environment for a fast numerical estimation of the scattered electromagnetic fields that could be useful for real data inversion.

Self-trapping effect on the excitonic and polaronic properties of a single-layer 2D metal-halide perovskite

Two-dimensional metal-halide perovskites (2DMHPs) have attracted tremendous interest due to their promising applications in the light-harvesting and light-emitting diodes. Recently, intensive experiment observations suggested the lattice of 2DMHPs should be very soft, such that photoexcitations would interact to the surrounding lattice distortions through the electron-lattice (e-l) couplings and led to the formation of self-trapped exciton (STE). However, the detailed formation mechanism has never been clearly clarified from the theoretical point of view. In this theoretical study, we build an effective tight-binding model for a single-layer 2DMHP (S2DMHP) with the e-l coupling considered as the Holstein type. This model successfully describes the ground-state optoelectronic properties and generates the primary non-linear elementary excitations which have been observed in a series of experiments. Our calculation reveals that the exciton state of a S2DMHP will exhibit significant polaronic characters. Depending on the e-l coupling strength and the level-occupancy configuration of the electron-hole pairs, such polaronic states could behave as either large polarons or small polarons. Large polarons range over multiple unit cells and induce the local deformation of the surrounding crystalline structure. Contrarily, small polarons are strongly bound and being trapped within the single octahedras. The existence of large and small polarons respectively explain the relative lower charge mobilities and the peculiar broadened white-light emissions in some selected S2DMHPs. The present work highlights the essential role of e-l couplings in determination of the excitonic properties of S2DMHPs and provides a theoretical foundation to deeply understand the optoelectronic behavior of S2DMHPs-based semiconductor devices.

Synthesis of Alkyl-Substituted Viologen Cation/Indanyl Anion Organic Charge Transfer Salts

Combination of ionic organic donor and acceptor to form crystalline salt can be an interesting strategy to obtain new types of organic semiconductors, since charge transfer (CT) excitonic properties are anticipated. We have previously achieved a novel CT salt from deprotonated 1,3-(bisdicyanomethylidene)indan anion (TCNIH-) and methyl viologen cation (MV2+) in a 2:1 composition. In this study, the n-alkyl chain length in viologen was systematically changed to find out the border for the evolution of CT character of the mixed salts. [1]Propyl to hexyl viologens (PrV to HxV) were synthesized by quaternization of 4,4’-bipyridine using the corresponding 1-haloalkanes in the yields of 60-62%, whereas methyl, ethyl, heptyl and octyl viologens (MV, EV, HpV, OV) were commercially available. Co-crystals with TCNIH- were precipitated by mixing with viologens at 2 : 1 ratio in water, filtrated and recrystallized from ethanolic solutions. While their crystal structures were examined on powder samples and single crystals, their optical properties were studied by measuring UV-vis and photoluminescence (PL) spectra for CT excitation.Co-crystals with TCNIH- were obtained for all viologens in a 2:1 ratio in the yields of 39-44%. While Na+ salt with TCNIH- preserves the character of the deprotonated TCNIH- in solution, showing a peak at around 590 nm and its absorption extending up to around 850 nm, those with RV2+ having short alkyl chains exhibit absorption towards NIR range and concomitant decrease of visible absorption, due to CT from TCNIH- to RV2+ (Fig. 1). A clear border can be found between PnV and HxV, as the CT absorption is significantly decreased when R is longer than Hx.Crystal structures of the mixed salts were identified as monoclinic for MV, BV, HxV salts, while triclinic for the others. The powder XRD data as well as melting points determined by differential scanning calorimetry indicated significant enlargement of donor-acceptor distances, decrease of melting point, and thereby weakened interaction to account for the observed CT characters. Coulombic interaction between donor and acceptor result in close packing of these co-crystals for their CT characters, whereas it is hindered when alkyl chains longer than Hx is introduced. However, PL from CT states was observed for all the compounds, as the salts with HxV, HpV and OV also showed clearly longer emission than that of Na salt, indicating primary excitation confined in TCNIH-, followed by its relaxation down to the CT states in such salts.Reference[1] E. Saito, et al., ECS Trans., 2018, 88, 301-311 Figure 1

Salt adaptability in a halophytic soybean (Glycine soja) involves photosystems coordination

BackgroundGlycine soja is a halophytic soybean native to saline soil in Yellow River Delta, China. Photosystem I (PSI) performance and the interaction between photosystem II (PSII) and PSI remain unclear in Glycine soja under salt stress. This study aimed to explore salt adaptability in Glycine soja in terms of photosystems coordination.ResultsPotted Glycine soja was exposed to 300 mM NaCl for 9 days with a cultivated soybean, Glycine max, as control. Under salt stress, the maximal photochemical efficiency of PSII (Fv/Fm) and PSI (△MR/MR0) were significantly decreased with the loss of PSI and PSII reaction center proteins in Glycine max, and greater PSI vulnerability was suggested by earlier decrease in △MR/MR0 than Fv/Fm and depressed PSI oxidation in modulated 820 nm reflection transients. Inversely, PSI stability was defined in Glycine soja, as △MR/MR0 and PSI reaction center protein abundance were not affected by salt stress. Consistently, chloroplast ultrastructure and leaf lipid peroxidation were not affected in Glycine soja under salt stress. Inhibition on electron flow at PSII acceptor side helped protect PSI by restricting electron flow to PSI and seemed as a positive response in Glycine soja due to its rapid recovery after salt stress. Reciprocally, PSI stability aided in preventing PSII photoinhibition, as the simulated feedback inhibition by PSI inactivation induced great decrease in Fv/Fm under salt stress. In contrast, PSI inactivation elevated PSII excitation pressure through inhibition on PSII acceptor side and accelerated PSII photoinhibition in Glycine max, according to the positive and negative correlation of △MR/MR0 with efficiency that an electron moves beyond primary quinone and PSII excitation pressure respectively.ConclusionTherefore, photosystems coordination depending on PSI stability and rapid response of PSII acceptor side contributed to defending salt-induced oxidative stress on photosynthetic apparatus in Glycine soja. Photosystems interaction should be considered as one of the salt adaptable mechanisms in this halophytic soybean.

Activation of EphB receptors contributes to primary sensory neuron excitability by facilitating Ca2+ influx directly or through Src kinase-mediated N-methyl-D-aspartate receptor phosphorylation.

EphrinB-EphB receptor tyrosine kinases have been demonstrated to play important roles in pain processing after peripheral nerve injury. We have previously reported that ephrinB-EphB receptor signaling can regulate excitability and plasticity of neurons in spinal dorsal horn, and thus contribute to spinal central sensitization in neuropathic pain. How EphB receptor activation influences excitability of primary neurons in dorsal root ganglion (DRG), however, remains unknown. Here, we report that EphB receptor activation facilitates calcium influx through N-methyl-D-aspartate receptor (NMDAR) dependent and independent manners. In cultured DRG cells from adult rats, EphB1 and EphB2 receptors were expressed in neurons, but not the glial cells. Bath application of EphB receptor agonist ephrinB2-Fc induced NMDAR-independent Ca influx, which was from the extracellular space rather than endoplasmic reticulum. EphB receptor activation also greatly enhanced NMDAR-dependent Ca influx and NR2B phosphorylation, which was prevented by pretreatment of Src kinase inhibitor PP2. In nerve-injured DRG neurons, elevated expression and activation of EphB1 and EphB2 receptors contributed to the increased intracellular Ca concentration and NMDA-induced Ca influx. Repetitive intrathecal administration of EphB2-Fc inhibited the increased phosphorylation of NR2B and Ca-dependent subsequent signals Src, ERK, and CaMKII as well as behaviorally expressed pain after nerve injury. These findings demonstrate that activation of EphB receptors can modulate DRG neuron excitability by facilitating Ca influx directly or through Src kinase activation-mediated NMDA receptor phosphorylation and that EphB receptor activation is critical to DRG neuron hyperexcitability, which has been considered critical to the subsequent spinal central sensitization and neuropathic pain.

Atomic Data for Calculation of the Intensities of Stark Components of Excited Hydrogen Atoms in Fusion Plasmas

Motional Stark effect (MSE) spectroscopy represents a unique diagnostic tool capable of determining the magnitude of the magnetic field and its direction in the core of fusion plasmas. The primary excitation channel for fast hydrogen atoms in injected neutral beams, with energy in the range of 25–1000 keV, is due to collisions with protons and impurity ions (e.g., He 2 + and heavier impurities). As a result of such excitation, at the particle density of 10 13 –10 14 cm − 3 , the line intensities of the Stark multiplets do not follow statistical expectations (i.e., the populations of fine-structure levels within the same principal quantum number n are not proportional to their statistical weights). Hence, any realistic modeling of MSE spectra has to include the relevant collisional atomic data. In this paper we provide a general expression for the excitation cross sections in parabolic states within n = 3 for an arbitrary orientation between the direction of the motion-induced electric field and the proton-atom collisional axis. The calculations make use of the density matrix obtained with the atomic orbital close coupling method and the method can be applied to other collisional systems (e.g., He 2 + , Be 4 + , C 6 + , etc.). The resulting cross sections are given as simple fits that can be directly applied to spectral modeling. For illustration we note that the asymmetry detected in the first classical cathode ray experiments between the red- and blue-shifted spectral components can be quantitatively studied using the proposed approach.

Eddy Current Damping System의 진동 저감 특성 평가

Generally, vibration absorber systems are composed of spring-mass systems to reduce the vibration of a structure, and there are also methods to simply increase damping to achieve a damping effect across a wide frequency band. One similar method is to use a mechanism in which the eddy current is converted into a mechanical damping effect. When an eddy current is generated by electromotive force due to magnetic flux change, the reaction force is generated by the eddy current’s circulation. In this study, the damping system using the reaction force was constructed to reduce the transmission of vibrations generating from internal fluid and the vibration reduction characteristics that are transmitted externally were analyzed. As a result, 8.2 % of the vibration reduction effect from primary excitation frequency was confirmed.

Bradykinesia in Alzheimer’s disease and its neurophysiological substrates

ObjectiveAlzheimer’s disease is primarily characterized by cognitive decline; recent studies, however, emphasize the occurrence of motor impairment in this condition. Here, we investigate whether motor impairment, objectively evaluated with kinematic techniques, correlates with neurophysiological measures of the primary motor cortex in Alzheimer’s disease. MethodsTwenty patients and 20 healthy subjects were enrolled. Repetitive finger tapping was assessed by means of a motion analysis system. Primary motor cortex excitability was assessed by recording the input/output curve of the motor-evoked potentials and using a conditioning-test paradigm for the assessment of short-interval intracortical inhibition and short-latency afferent inhibition. Plasticity-like mechanisms were indexed according to changes in motor-evoked potential amplitude induced by the intermittent theta-burst stimulation. ResultsPatients displayed slowness and altered rhythm during finger tapping. Movement slowness correlated with reduced short-latency afferent inhibition in patients, thus suggesting that degeneration of the cholinergic system may also be involved in motor impairment in Alzheimer’s disease. Moreover, altered movement rhythm in patients correlated with worse scores in the Frontal Assessment Battery. ConclusionThis study provides new information on the pathophysiology of altered voluntary movements in Alzheimer’s disease. SignificanceThe study results suggest that a cortical cholinergic deficit may underlie movement slowness in Alzheimer’s disease.

Triplet Shelving in Fluorescein and Its Derivatives Provides Delayed, Background-Free Fluorescence Detection

Fluorescence from the xanthene dyes rose bengal, erythrosine B, eosin Y, and fluorescein is modulated by reversibly optically populating and depopulating their long-lived triplet states through coillumination with a second, long-wavelength laser. Here, we show that repumping the S1 state from the triplet generates strong, nanosecond-lived optically activated delayed fluorescence (OADF), microseconds to milliseconds after primary pulsed excitation. This time-delayed emission upon long-wavelength illumination generates fluorescence after triplet shelving and is a major contribution to fluorescence enhancement/modulation. The time-delayed and background-free OADF component is further increased using a >1 μs burst continuous wave excitation scheme to increase the steady-state triplet populations, yielding strong OADF even from strongly emissive fluorescein. Because emission is delayed long after the high-energy primary excitation, yellow-orange fluorescence is readily observed on zero background. As OADF generation depends on the triplet quantum yields and the reverse intersystem crossing rates, we directly probe the usually difficult-to-measure photophysics, create new zero-background detection schemes, and increase OADF through tailored excitation schemes, all improving sensitivity. The excellent match between experiments and simulations demonstrates the promise of these studies for OADF characterization, while enabling us to determine that OADF (in contrast to ground-state recovery and re-excitation) is the major component of fluorescence enhancement for xanthenes studied with triplet quantum yields exceeding 0.1.

Universal inelastic electron scattering cross‐section including extrinsic and intrinsic excitations in XPS

AbstractThe high importance of X‐ray photoelectron spectroscopy (XPS) in surface analysis is well established. In XPS, the shape of the measured peaks is affected by two classes of energy loss: extrinsic losses because of the transport of photoelectrons in the matter and intrinsic losses because of the sudden creation of the static core hole. In order to perform a quantitative, comprehensive determination of the zero‐energy loss spectrum, a systematic and physically meaningful background subtraction method must be used. In this paper, we propose a universal analytical expression to model the energy loss cross section of the emitted photoelectrons for transition metals and their oxides. The proposed expression is a generalization of the well‐known Tougaard's universal inelastic scattering cross section to also account for the intrinsic losses. We demonstrate the use of this to determine the primary excitation spectra of several transition metals and their oxides, and we compare the results with a more accurate calculation based on the dielectric response model for XPS.

Magnetic field analysis of Primary Permanent Magnet Linear Motor Based on Halbach Distribution

The rail transit system driven by linear motor has outstanding advantages in climbing ability, traction performance, vibration and noise. However, with the increase of traffic travel and other situations, how to ensure that the linear motor still has a large thrust and stability in the air gap condition is the key technical problem. In order to solve this problem, three Halbach permanent magnet array structures are proposed and applied to the magnetic barrier coupled primary permanent magnet unilateral excitation linear motor (MBCPPMUELM). The finite element software is used for simulation and analysis. By comparing the harmonic distribution of air gap magnetic field of the three Halbach permanent magnet array motors, a topology structure with high magnetic field modulation effect is obtained It provides a useful reference for the further design and analysis of this kind of motor.

Study of the Ability of an Electromagnetic Flowmeter Based on Step Excitation to Overcome Slurry Noise

An electromagnetic flowmeter (EMF) can be used to measure the speed of slurry fluid. In this paper, according to Maxwell’s equations and the dB/dt vortex electric field, a step excitation scheme is proposed. The original excitation process of the primary excitation current rise time is divided into a two-step excitation process. Without increasing the excitation current rise time, the equivalent excitation frequency is increased by increasing the primary dB/dt . This method can enhance the EMF’s ability to overcome slurry noise. The paper analyzes the design parameters of the step excitation scheme and designs the software and hardware. After that, the paper compares the step excitation scheme with the three-value rectangular wave excitation scheme based on wavelet transform signal processing. Experiments show that the step excitation EMF has a lower steady-state fluctuation rate when measuring mortar and has a stronger ability to overcome slurry noise. Additionally, the step excitation EMF and Yokogawa AXF 040G EMF are compared experimentally. Through flow calibration, clean water measurement, mortar measurement and dynamic response experiment, it is verified that the step excitation EMF has the ability to enhance the resistance to slurry noise at the same excitation frequency.

Inelastic floor spectra for designing anchored acceleration-sensitive nonstructural components

In this study, inelastic floor spectra are developed for designing acceleration-sensitive nonstructural components (NSCs). The parameters response modification (reduction) factor, $$ R_{\text{cc}} $$, and inelastic displacement ratio, $$ C_{\text{cc}} $$, are evaluated to quantify the effects of NSCs inelasticity on their seismic-induced force and displacement demands, respectively. The results of the conducted response history analyses illustrate that the inelastic behavior of NSCs can significantly de-emphasize the effects of their tuning period ratio and viscous damping ratio, and of the characteristics of the primary structure and ground excitation. Due to the quasi-harmonic characteristic of building floor motions, NSC inelasticity is more effective for NSCs attached to buildings than for those attached to the ground. NSC inelasticity is most effective for a low-damping roof-mounted NSC tuned to the first modal period of an elastic building (i.e., the most critical NSC from the design point of view). Adopting even a mild level of inelasticity for tuned NSCs not only decreases their seismic force demands significantly but also reduces their displacement demands. For non-tuning conditions, particularly for rigid NSCs, achieving even a relatively small $$ R_{\text{cc}} $$ (i.e., a small reduction in force demand) leads to a significant increase in NSC displacement and ductility demands suggesting that these NSCs should be designed to remain elastic. Results illustrate that the amplitude of $$ R_{\text{cc}} $$ and $$ C_{\text{cc}} $$ depends on the tuning ratio, viscous damping, and level of inelasticity of NSCs, and to a lesser extent, on the characteristics of the primary structure and ground motion. Simplified yet reliable equations are proposed for the estimation of the parameter $$ R_{\text{cc}} $$ for non-rigid NSCs with different levels of inelasticity and viscous damping.

Simultaneous Resonances of Suspended Cables Subjected to Primary and Super-Harmonic Excitations in Thermal Environments

This paper concerns with a suspended cable in thermal environments under bi-frequency harmonic excitations, with a focus placed on the effect of temperature changes on one type of simultaneous resonance. First, the nonlinear equation of motion in thermal environments is obtained for the in-plane displacement of the cable. Then, the Galerkin method is employed to reduce the partial differential equation to an ordinary one. Second, based on the discretized form of the governing equation, the method of multiple scales is employed to obtain the second-order approximate solutions, with the stability characteristics determined. Third, numerical results are presented by using the perturbation method, together with numerical integration by the following means: frequency-response curves, time-displacement curves, phase-plane diagrams, and Poincare sections. The direct integration method is utilized to verify the results obtained by the perturbation method, while revealing more nonlinear dynamic behaviors induced by temperature changes. Both the softening and/or hardening behaviors, and the switching between them are observed for the cable in thermal environments. The response amplitude of the cable is very sensitive to temperature changes, but the number of circles in the phase diagrams and the number of cluster points in Poincaré sections is independent of the thermal effects in most cases. Finally, the vibration characteristics of the cable for different thermal expansion coefficients and temperature-dependent Young’s moduli are also investigated.

Suppression of chaos by incommensurate excitations: Theory and experimental confirmations

We experimentally, numerically, and theoretically characterize the effectiveness of incommensurate excitations at suppressing chaos in damped driven systems. Specifically, we consider an inertial Brownian particle moving in a prototypical two-well potential and subjected to a primary (chaos-inducing) harmonic excitation and a suppressory incommensurategeneric (non-harmonic) excitation. We show that the effective amplitude of the suppressory excitation is minimal when the impulse transmitted by it is near its maximum, while its value is rather insensitive to higher-order convergents of the irrational ratio between the involved driving periods. Remarkably, the number and values of the effective initial phase difference between the two excitations are independent of the impulse while they critically depend on each particular convergent in a complex way involving both the approximate frustration of chaos-inducing homoclinic bifurcations and the maximum survival of relevant spatio-temporal symmetries of the dynamical equation.

Charge Carrier Injection Electroluminescence with CO-Functionalized Tips on Single Molecular Emitters.

We investigate electroluminescence of single molecular emitters on NaCl on Ag(111) and Au(111) with submolecular resolution in a low-temperature scanning probe microscope with tunneling current, atomic force, and light detection capabilities. The role of the tip state is studied in the photon maps of a prototypical emitter, zinc phthalocyanine (ZnPc), using metal and CO-metal tips. CO-functionalization is found to have an impact on the resolution and contrast of the photon maps due to the localized overlap of the p-orbitals on the tip with the molecular orbitals of the emitter. The possibility of using the same CO-functionalized tip for tip-enhanced photon detection and high resolution atomic force is demonstrated. We study the electroluminescence of ZnPc, induced by charge carrier injection at sufficiently high bias voltages. We propose that the distinct level alignment of the ZnPc frontier orbitals with the Au(111) and Ag(111) Fermi levels governs the primary excitation mechanisms as the injection of electrons and holes from the tip into the molecule, respectively. These findings put forward the importance of the tip status in the photon maps and contribute to a better understanding of the photophysics of organic molecules on surfaces.

An Estimation of Pedestrian Action on Footbridges Using Computer Vision Approaches

Vibration serviceability of footbridges is important in terms of fitness for purpose. Human-induced dynamic loading is the primary excitation of footbridges and has been researched with traditional sensors, such as inertial sensors and force plates. Along with the development of computer hardware and algorithms, e.g. machine learning, especially deep learning, computer vision technology improves rapidly and has potential application to the problem. High precision pedestrian detection can be realized with various computer vision methods, corresponding to different situations or demands. In this paper, two widely recognised computer vision approaches are used for detecting body centre of mass and ankle movement, to explore the potential of these methods on human-induced vibration research. Consumer-grade cameras are used without artificial markers, to take videos for further processing and wearable inertial sensors were used to validate and evaluate the computer vision measurements.