Single-shot time-gated fluorescence lifetime imaging using three-frame images

Qualitative and quantitative measurements of complex flows demand for fast single-shot fluorescence lifetime imaging (FLI) technology with high precision. A method, single-shot time-gated fluorescence lifetime imaging using three-frame images (TFI-TGFLI), is presented. To our knowledge, it is the first work to combine a three-gate rapid lifetime determination (RLD) scheme and a four-channel framing camera to achieve this goal. Different from previously proposed two-gate RLD schemes, TFI-TGFLI can provide a wider lifetime range 0.6 ~ 13ns with reasonable precision. The performances of the proposed approach have been examined by both Monte-Carlo simulations and toluene seeded gas mixing jet diagnosis experiments. The measured average lifetimes of the whole excited areas agree well with the results obtained by the streak camera, and they are 7.6ns (N2 = 7L/min; O2 < 0.1L/min) and 2.6ns (N2 = 19L/min; O2 = 1L/min) with the standard deviations of 1.7ns and 0.8ns among the lifetime image pixels, respectively. The concentration distributions of the quenchers and fluorescent species were further analyzed, and they are consistent with the experimental settings

A comparative analysis of morphology, microstructure, and volatile metabolomics of leaves at varied developmental stages in Ainaxiang (Blumea balsamifera (Linn.) DC.)

IntroductionAinaxiang (Blumea balsamifera (Linn.) DC.) is cultivated for the extraction of (-)-borneol and other pharmaceutical raw materials due to its abundant volatile oil. However, there is limited knowledge regarding the structural basis and composition of volatile oil accumulation in fresh B. balsamifera leaves.MethodsTo address this problem, we compare the fresh leaves’ morphology, microstructure, and volatile metabonomic at different development stages, orderly defined from the recently unfolded young stage (S1) to the senescent stage (S4).Results and discussionDistinct differences were observed in the macro-appearance and microstructure at each stage, particularly in the B. balsamifera glandular trichomes (BbGTs) distribution. This specialized structure may be responsible for the accumulation of volatile matter. 213 metabolites were identified through metabolomic analysis, which exhibited spatiotemporal accumulation patterns among different stages. Notably, (-)-borneol was enriched at S1, while 10 key odor metabolites associated with the characteristic balsamic, borneol, fresh, and camphor aromas of B. balsamifera were enriched in S1 and S2. Ultra-microstructural examination revealed the involvement of chloroplasts, mitochondria, endoplasmic reticulum, and vacuoles in the synthesizing, transporting, and storing essential oils. These findings confirm that BbGTs serve as the secretory structures in B. balsamifera, with the population and morphology of BbGTs potentially serving as biomarkers for (-)-borneol accumulation. Overall, young B. balsamifera leaves with dense BbGTs represent a rich (-)-borneol source, while mesophyll cells contribute to volatile oil accumulation. These findings reveal the essential oil accumulation characteristics in B. balsamifera, providing a foundation for further understanding

Model Predictive Control Based on Parametric Disturbance Compensation

Model predictive control (MPC) has been widely implemented in the motor because of its simple control design and good results. However, MPC relies on the permanent magnet synchronous motor (PMSM) system model. With the operation of the motor, parameter drift will occur due to temperature rise and flux saturation, resulting in model mismatch, which will seriously affect the control accuracy of the motor. This paper proposes a model predictive control based on parameter disturbance compensation that monitors system disturbances caused by motor parameter drift and performs real-time parameter disturbance compensation. And the frequency-domain method was used to analyze the convergence and filterability of the model. The Bode diagram of measurement error and input disturbance was studied when the parameters were underdamped, critically damped, and overdamped. Guidelines for parameter selection are given. Simulation results show that the proposed method has good dynamic performance, anti-interference ability, and parameter robustness, which effectively avoids the current static difference and oscillation problems caused by parameter changes

Research on missile consumption in wartime with the airport runway as the target

To solve the problem of insufficient research on missile consumption in wartime with the airport runway as the target, this paper takes the airport runway as the target, taking the invalidation probability as the expected target, and adopting conventional missiles with submunitions. In combination with penetration and anti-missile countermeasures, this paper publicly proposes the consumption&nbsp;calculation method and model for the first time, and the multi-wave strikes strategy and calculation method are proposed either. The model is verified by combining the specific airport runway, fighter jet model and missile parameters. The experiment calculates the total consumption&nbsp;and the corresponding probability of destroying the target, as well as the total strike wave and the corresponding probability of destroying the target. The results prove the effectiveness and accuracy of the method and model, and provide an important basis for the sufficient amount of missiles to attack airport runways in wartime

Enhanced performance of polymer solar cells by dipole-assisted hole extraction

Polymer solar cells (PSCs) with different anode buffer layers were fabricated to investigate dipoleassisted hole extraction on the performance improvement of PSCs. The power conversion efficiency (PCE) of PSCs was increased from 4.77% to 6.18% with 29.6% improvement due to the increased short circuit current density (J) from 12.00 to 15.65 mA/cm2 induced by the oriented LiF dipole-assisted hole extraction. More hole could be swept-out from the active layers by oriented LiF dipole/PEDOT:PSS combined anode buffer layers. The dipole-assisted hole extraction could be further demonstrated from the J-V curves of hole-only devices with different anode buffer layers. (C)2014 Elsevier B.V. All rights reserved

Improved Performance of Photomultiplication Polymer Photodetectors by Adjustment of P3HT Molecular Arrangement

A series of photomultiplication (PM)-type polymer photodetectors (PPDs) were fabricated with polymer poly­(3-hexylthiophene)–[6,6]-phenyl-C₇₁-butyric acid methyl ester (P3HT–PC₇₁BM) (100:1, w/w) as the active layers, the only difference being the self-assembly time of the active layers for adjusting the P3HT molecular arrangement. The grazing incidence X-ray diffraction (GIXRD) results exhibit that P3HT molecular arrangement can be adjusted between face-on and edge-on structures by controlling the self-assembly time. The champion EQE value of PPDs, based on the active layers without the self-assembly process, arrives at 6380% under 610 nm light illumination at −10 V bias, corresponding to the face-on molecular arrangement of P3HT in the active layers. The EQE values of PPDs were markedly decreased to 1600%, along with the self-assembly time up to 12 min, which should be attributed to the variation of absorption and hole transport ability of the active layers induced by the change of P3HT molecular arrangement. This finding provides an effective strategy for improving the performance of PM-type PPDs by adjusting the molecular arrangement, in addition to the enhanced trap-assisted charge-carrier tunneling injection

Cooperative enhancement of optical nonlinearities in a porphyrin derivative bearing a pyrimidine chromophore at the periphery

A novel porphyrin derivative bearing one D-π-A-π-D pyrimidine chromophore at the periphery was designed, prepared, and studied using the Z-scan technique, the results showing that this compound exhibits enhanced nonlinear optical (NLO) absorption, refr

Increased optical nonlinearities of graphene nanohybrids covalently functionalized by axially-coordinated porphyrins

Two graphene oxide (GO)-based nanohybrid materials possessing covalent linkages to axially-coordinated tetraphenylporphyrin (TPP), GO-TPP, were prepared and were characterized by Fourier transform infrared (FT-IR), Ultraviolet-visible (UV-Vis) absorption, steady state fluorescence, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), thermogravimetric analysis (TGA), elemental analysis and Raman spectroscopic techniques. The nonlinear optical properties and optical limiting performance of GO, GO-TPP nanohybrids and the free porphyrins dihydroxotin(IV) tetraphenylporphyrin (SnTPP) and the phosphorus-cored porphyrin (PTPP) were investigated using nanosecond and picosecond Z-scan measurements at 532 nm. At the identical mass concentration of 0.2 mg mL-1, GO-TPP nanohybrids exhibited enhanced nonlinear optical properties and optical limiting performance, ascribed to a combination of nonlinear scattering and/or two-photon absorption with reverse saturable absorption, and the photo-induced electron or energy transfer from the electron-donor porphyrin moiety to the acceptor graphene