We report a tunable magnetoresistance by uniformly mixing strong-spin-orbital-coupling molecule fac-tris (2-phenylpyridinato) iridium $[\mathrm{Ir}(ppy{)}_{3}]$ and weak-spin-orbital-coupling polymer poly($N$-vinyl carbazole) (PVK). Three possible mechanisms, namely charge transport distribution, energy transfer, intermolecular spin-orbital interaction, are discussed to interpret the $\mathrm{Ir}(ppy{)}_{3}$ concentration-dependent in $\mathrm{PVK}+\mathrm{Ir}(ppy{)}_{3}$ composite. The...

Nanosecond laser-induced breakdown spectroscopy (ns-LIBS) is employed for quantitative local fuel-air (F/A) ratio (i.e., of actual fuel-to-oxidizer mass over at stoichiometry, measurements in well-characterized methane-air flames pressures 1-11 bar). We selected nitrogen and hydrogen atomic-emission lines 568 nm 656 nm, respectively, to establish a correlation between the line intensities F/A ratio. have investigated effects laser-pulse energy, camera gate delay, pressure on sensitivity,...

This letter reports the experimental results of enhanced electroluminescence (EL) and photovoltaic (PV) response upon doping single-wall carbon nanotubes (SWNTs) into conjugated polymer poly[2-methoxy-5-(2′-ethylhexyloxy)-1, 4-phenylenevinylene] (MEHPPV) based on single-layer light-emitting diodes. We found that dispersed SWNTs result in two processes: charge transport exciton dissociation at tube-chain interface SWNT/polymer composites. The detailed EL PV studies indicate low SWNT...

Two-dimensional (2D) Raman scattering at 10 kHz in non-reacting flow mixtures is demonstrated by employing a burst-mode laser with long-duration pulse of about 70 ns and energy 750 mJ 532 nm. To avoid optical breakdown, the width was varied range 10-1000 ns. The effects shape, energy, harmonic conversion on 2D measurements are also studied. applications high-speed, single-shot, imaging CH4 H2 jets N2 elevated pressures demonstrated. In addition, scalar dissipation rate 20 bar determined,...

This letter reports the modifications of spin-orbital coupling and magnetoresistance conjugated polymer upon deposition metal electrode based on organic light-emitting diodes poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene]. We find that reverse bias yields a largely increased when electron-hole capture zone is away from as compared to forward with close electrode. The electroluminescence suggests deposited atoms enhance at polymer/metal interface consequently lead dependent...

Magnetic nanoparticles of CoFe are used as dopants to enhance the quantum efficiency electroluminance in a single layer organic light emitting device (OLED). The enhancement increases with both increasing density and external magnetic field. For given OLED 0.1wt% doping, reaches ∼27% ∼32% without field, respectively. origin these improvements could be attributed simultaneous portion excitons among total charge carriers fraction singlets

We report the direct measurements of methyl radicals (CH(3)) in methane/air flames at atmospheric pressure by using coherent microwave Rayleigh scattering (Radar) from Resonance Enhanced Multi-Photon Ionization (REMPI), also known as Radar REMPI technique. A tunable dye laser was used to selectively induce (2 + 1) ionization (CH(3), 3p(2)A(2)('')0(0)(0) band) a near adiabatic and premixed laminar flame, generated Hencken burner. In situ electrons were made non-intrusively homodyne...

Here we present quantitative measurements of total electron numbers in laser-induced air breakdown at pressures ranging from atmospheric to 40 barg by 10 ns and 100 ps laser pulses. A quantifiable definition for the threshold is identified a sharp increase measurable via dielectric-calibrated coherent microwave scattering. For pulse, defined as number ∼106. This decreases with an pressure photon energy (shorter wavelength), which consistent theory initial multiphoton ionization subsequent...

Quantitative, kiloherz-rate measurement of carbon monoxide mole fractions by femtosecond two-photon, laser-induced fluorescence (TP-LIF) was demonstrated in high-pressure, luminous flames over a range fuel-air ratios. Femtosecond excitation at 230.1 nm used to pump CO two-photon rovibrational X1Σ+→B1Σ+ transitions the Hopfield-Birge system and avoid photolytic interferences with irradiance ∼1.7×1010 W/cm2. The effects wavelength, detection scheme, potential sources de-excitation were also...

Laser-induced breakdown spectroscopy (LIBS) evaluates the emission spectra of ions, radicals, and atoms generated from molecules by incident laser; however, LIBS signal is unstable at elevated pressures. To understand cause instability, we perform simultaneous time-resolved measurements electron density for nitrogen (568 nm) hydrogen (656 high pressure (up to 11 bars). From correlations between number density, find that uncontrollable generation excess electrons causes instability in...

We report a magnetic field-dependent electroluminescence (EL) induced by ferromagnetic Co53Pt47 nanowires in fluorescent conjugated polymer poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] and phosphorescent iridium-complex Ir(ppy)3 molecules. The photoluminescence EL studies indicate that the dispersed CoPt increase singlet-to-triplet exciton ratio organic semiconductors, suggesting spin-polarized holes were injected into molecules from under electrical excitation. Therefore, use...

We report a spin-polarized hole injection into organic semiconductor poly[2-methoxy-5-(${2}^{\ensuremath{'}}$-ethylhexyloxy)-1,4-phenylenevinylene (MEHPPV) layer from cobalt (Co) nanoscale clusters based on electroluminescence (EL) studies at liquid nitrogen temperature. The magnetic field effect EL intensity indicates that the spin essentially increases singlet-to-triplet exciton ratio in semiconductors. Co size-dependent shows spin-injection efficiency decreases rapidly when percolate to...

Here we report nonintrusive local rotational temperature measurements of molecular oxygen, based on coherent microwave scattering (radar) from resonance-enhanced multiphoton ionization (REMPI) in room air and hydrogen/air flames. Analyses the line strengths two-photon oxygen C3Π(v=2)←X3Σ(v′=0) transition have been used to determine hyperfine state distribution ground X3Σ(v′=0) state. Rotationally resolved 2+1 REMPI spectra at different temperatures were obtained experimentally by radar...

Nonintrusive spatially resolved rotational temperature measurements in an atmospheric air microdischarge are presented. The were based on coherent microwave Rayleigh scattering (Radar) from resonance-enhanced multiphoton ionization of molecular oxygen. open DC source operated a stable “normal-glow” mode and pin-to-pin electrodes spaced 1.3 mm apart. second harmonic tunable dye laser beam was focused between the two scanned 286 288 nm. Coherent used to collect two-photon spectra O2 at C3Π(v =...

Knowledge of optical effects accompanying hypersonic flight conditions is critical importance to ensure reliable operation on-board instrumentation. This paper presents results calculations scalar polarizability dependence on vibrational non-equilibrium in molecular nitrogen and oxygen. The are evaluated the basis a semi-classical model for polarizability. It shown that, depending translational populations, changes excess normal density temperature scaling can be around 1%–5% at moderate gas...

Coherent microwave Rayleigh scattering (Radar) from resonance-enhanced multiphoton ionization (REMPI) was demonstrated to directly and nonintrusively measure singlet delta oxygen, O(2)(a(1)Δ(g)), with high spatial resolution. Two different approaches, photodissociation of ozone discharge plasma in an argon oxygen flow, were utilized for O(2)(a(1)Δ(g)) generation. The d(1)Π(g)←a(1)Δ(g) (3-0) (1-0) bands detected by Radar REMPI two flow conditions. Quantitative absorption measurements using...

Amplification of laser-induced plasma in air is demonstrated utilizing resonant laser ionization and avalanche ionization. Molecular oxygen ionized by a low-energy pulse employing (2 + 1) resonance-enhanced multi-photon (REMPI) to generate seed electrons. Subsequent molecular nitrogen significantly amplifies the plasma. In this plasma-amplification effect, three-body attachments dominate electron-generation -loss processes, while either or argon acts as third body with low electron affinity....

In this Letter, acoustic detection of resonance-enhanced multiphoton ionization (A-REMPI) is characterized and used to measure spatially resolved O2 rotational temperature in air. The signal generated using REMPI air detected by a single microphone operating within the audible range. Compared electron number measurements coherent microwave scattering, nonlinear light absorption subsequent local pressure perturbation are captured microphone. A typical cycle compression rarefication wave...